Residual effect of lambdacyhalothrin on Triatoma infestans.

Insecticidal residual effect and triatomine infestation rates in houses of a community fumigated with lambdcyhalothrin (Icon) are reported. No mortality was observed in 5th-instar Triatoma infestans nymphs in 72-hr exposure test on three different surfaces, one month after fumigation for a dose of 31.5 mg am/m2. However, during post-exposure observation a mortality of 60% was recorded for those insect exposed on sprayed woodboard. The results observed with mud-containing treated walls, were markedly poorer (0% of mortality). Twelve month after spraying 40% of mortality was observed on first-instar T. infestans nymphs in 72-hr exposure test on woodboard, but lower mortality rates were observed in mud-containing materials. When the effect of deltamethrin (109 mg ai/m2) and lambdcyhalothrin (94 mg ai/m2) was compared, the former did not appear to be superior at similar loads. Both have showed a mortality rate of 30% on 5th-instar T. infestans nymphs three months post-fumigation. The dose utilized in the field fumigation was enough to get a significant (p < 0.0001) control of triatomine domestic infestation, since it was sufficient to keep 95% of the houses uninfested throughout 21 months following treatment, when compared with baseline situation. A remarkable knock-down effect on adult and nymphs forms of the insect and a high in situ mortality were observed as a result of its application, even at very low doses.

Acute Chagas' disease in non-human primates. 1. Chronology of clinical events, clinical chemistry, ECG, radiology, parasitemia, and immunological parameters in the Cebus apella monkey.

Forty Cebus apella monkeys free from Chagas' disease were subcutaneously infected with 3 x 10(5) trypomastigotes of the Ypsilon strain of T. cruzi and followed-up for 6 months. Seventeen monkeys were controls. Body weight, temperature, direct parasitemia (DP), IgM and IgG were determined weekly. Hematology was performed weekly up to day 40 p.i. and monthly thereafter. Clinical chemistry was performed every two weeks up to day 33 p.i. and monthly thereafter. ECG was performed weekly up to day 47 p.i. and at 2,3, and 6 months p.i. Chest X-ray was done at 45 days, 4 and 6 months p.i. Xenodiagnosis was only performed after two negative DP. All infected monkeys developed fever, beginning 6.0 +/- 0.6 day p.i. and lasting 21.9 +/- 6.7 days, and lost 14% of their body weight the first month, 11% the third month and 7% the 6th month. DP was already detected 4.4 +/- 0.29 days after infection and it was detectable in all monkeys up to 96.0 +/- 6.9 days p.i. Cyclical peaks of parasitemia were observed throughout the study. IgM and IgG titers which permitted a diagnosis of T. cruzi infection occurred at 33.0 +/- 2.9 days p.i., respectively. Fifty-seven percent of infected monkeys presented ECG alterations one week after inoculation reaching a maximum of 86% at the third week. A normocytic, normochromic anemia was observed in all monkeys being significantly (p less than 0.02) more severe in the infected animals. No effects of T. cruzi on the clinical chemistry were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of environmental lighting on the function of the pineal gland.

The pineal has undergone marked changes as vertebrates have evolved from amphibians to mammals. The amphibian pineal is a photoreceptive organ which sends nervous information to the brain via pineal nerves: the mammalian and avian pineal have no direct connections to the CNS and their metabolism is controlled by an indirect pathway involving their peripheral sympathetic nerves. In addition, the pinealocytes of some birds also function as photoendocrine transducers, i.e., they convert a photic input reaching them directly through the skull into a hormone output. Through the secretion of melatonin and of some as yet undefined low molecular weight peptides, the pineal participates in the control of other neuroendocrine rhythms such as seasonal cycles in gonadal function.

Effects of environmental lighting on the function of the pineal gland

The pineal has undergone marked changes as vertebrates have evolved from amphibians to mammals. The amphibian pineal is a photoreceptive organ which sends nervous information to the brain via pineal nerves: the mammalian and avian pineal have no direct connections to the CNS and their metabolism is controlled by an indirect pathway involving their peripheral sympathetic nerves. In addition, the pinealocytes of some birds also function as photoendocrine transducers, i.e., they convert a photic input reaching them directly through the skull into a hormone output. Through the secretion of melatonin and of some as yet undefined low molecular weight peptides, the pineal participates in the control of other neuroendocrine rhythms such as seasonal cycles in gonadal function.

Effects of environmental lighting on the function of the pineal gland.

The pineal has undergone marked changes as vertebrates have evolved from amphibians to mammals. The amphibian pineal is a photoreceptive organ which sends nervous information to the brain via pineal nerves: the mammalian and avian pineal have no direct connections to the CNS and their metabolism is controlled by an indirect pathway involving their peripheral sympathetic nerves. In addition, the pinealocytes of some birds also function as photoendocrine transducers, i.e., they convert a photic input reaching them directly through the skull into a hormone output. Through the secretion of melatonin and of some as yet undefined low molecular weight peptides, the pineal participates in the control of other neuroendocrine rhythms such as seasonal cycles in gonadal function.