Forkhead box protein 3(+) regulatory T cells and Helios(+) subset in perinatally acquired HIV.

Forkhead box protein 3 (FoxP3)(+) regulatory T cells (Tregs ) are important not only in regulating the development of autoimmune conditions, but also in chronic infectious diseases. Given their cardinal function in suppressing immune activation, research has focused upon whether they play a detrimental role in chronic infections, particularly HIV. While the role of Tregs in HIV has been investigated intensively, it remains an unresolved topic. However, it is generally accepted that Tregs are susceptible to HIV infection and are preferentially preserved over conventional CD4(+) T cells. It is unknown whether the peripheral-induced or the thymic-derived Tregs are more susceptible to HIV cytotoxicity. It has been recognized that Tregs can be segregated into two subsets based on Helios expression, with the vast majority being Helios(+) . This study examines the impact of HIV infection on total Tregs and their Helios subsets in a perinatal-acquired HIV-infected paediatric population. The finding indicates a selective expansion or survival of Tregs in association with CD4 depletion and increased viraemia. The Helios(+) and Helios(-) subsets within Tregs appear to be equally affected. However, the Helios(+) Tregs seem to be more preserved in patients with low CD4(+) ≤ 25% and detectable plasma HIV RNA >20 copies/ml. In this group, the frequencies of Tregs are increased, but their numbers appear insufficient to restrain immune activation. In conclusion, our findings suggest that both Helios subsets of Tregs are susceptible to HIV infection and are preferentially preserved compared to conventional CD4(+) T cells.

Lacrimal fluid peroxidase activity during the menstrual cycle.

PURPOSE: The aim of this work was to investigate peroxidase activity in human tears during the various phases of the menstrual cycle. For comparative purposes saliva was also examined. METHODS: Tear fluids and saliva from 10 healthy volunteers 23-41 years of age (mean: 28.2 years), with regular menstrual cycles were sampled for the duration of at least two complete cycles. Menstrual cycles and ovulation periods were evaluated by measuring morning body temperature and hormone levels in plasma and urine. Unstimulated tears and unstimulated saliva were collected in the morning every two days. Peroxidase activity was monitored according to the 5,5'-dithiobis, 2-nitrobenzoic acid thiocyanate (Nbs-SCN) method and the protein content was determined by the Bradford method. RESULTS: Peroxidase activity in tears, expressed as U/mL, was significantly (p <.05) higher during the preovulatory and luteal phases with respect to the menses, whilst total protein content remained almost unchanged throughout all phases. A positive correlation was found between lacrimal fluid peroxidase activity and 17beta-estradiol plasma levels (p <.001). Salivary peroxidase activity did not show such estrogen-related changes. CONCLUSIONS: Our findings report cyclic variations in peroxidase activity in human tears during the menstrual cycle. Such cycling seems to reflect variations of 17 beta-estradiol plasma levels. These results suggest that a regulation of lacrimal fluid peroxidase by 17 beta-estradiol could be one possible cause for the female gender predilection in some ocular diseases, such as keratoconjunctivitis sicca.

Induced acute ocular hypertension: mode of retinal cell degeneration.

The effects of experimental hypertension on retinal cells were studied. Evaluation was made of IOP levels and degree of cell damage by cytochemical and DNA analysis, and degeneration modes: necrosis and apoptosis.

Brain protein synthesis in rabbits following low level aluminium exposure.

1. Infant rabbits received s.c.injections 3 times weekly of low doses of aluminium (A1) maltolate (0.5-1.5 mg Al/kg body wt) or aluminium lactate (8 mg Al/kg body wt) from 5 or 10 days of age to 14 or 22 days of age. 2. Brain was used to provide a cell-free protein synthesizing system and this system exhibited increased activity in preparations from Al-exposed infants. The mRNA fraction obtained from the brain polysomal RNA also was more active following Al exposure. 3. The synthesis of immunoprecipitable calmodulin was significantly elevated.