Platelet interactions with viruses and parasites

Abstract

While the interactions between Gram-positive bacteria and platelets have been well characterized, there is a paucity of data on the interaction between other pathogens and platelets. However, thrombocytopenia is a common feature with many infections especially viral hemorrhagic fever. The little available data on these interactions indicate a similarity with bacteria-platelet interactions with receptors such as FcγRIIa and Toll-Like Receptors (TLR) playing key roles with many pathogens. This review summarizes the known interactions between platelets and pathogens such as viruses, fungi and parasites.     

Partial Portal Vein Ligation Plus Thioacetamide: A Method to Obtain a New Model of Cirrhosis and Chronic Portal Hypertension in the Rat

To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n?=?10), 2 [triple partial portal vein ligation (TPVL); n?=?9], 3 (TAA; n?=?11), and 4 (TPVL plus TAA; n?=?9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL?+?TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations.     

The nurse's work in the care plan for families in the mountains

In this investigation is demonstrated that the nurse needs, in order to carry out a successful work, to learn about the composition of the population of the area under her care. In Patana, a Maisí municipality with 165 inhabitants, 93 male and 72 females, prevailing ninth grade school level and an initial low hygienic culture level, which is considered as regular at the present time, intestinal parasitism and malnutrition are the main diseases in the zone. It is well demonstrated that there is a wide relationship between hygienic conditions at home and community and the incidence of the fore-mentioned diseases and that the educational work performed by the nurse in the area under her care exerts a positive influence, but the support of grassroot mass organizations is required.     

Non-linear tissue binding of amikacin in rats: the effect of renal impairment

Amikacin levels in serum and tissues were determined in 115 Wistar rats, 70 with normal renal function (NRF) and the remaining 45 with terminal renal impairment (TRI). The results obtained in the animals with NRF show an accumulation of the antibiotic in all the tissues studied as compared with plasma levels, specially in the renal cortex and medulla. In the rats with TRI important alterations in the plasma and tissue kinetics of the antibiotics were observed. The plasma kinetics of amikacin in rats with TRI are characterised by significant alterations in the pharmacokinetic parameters, specially those defining the distribution processes of the antibiotic. In the tissues of the latter, a significant increase in the antibiotic concentration takes place, particularly in the renal cortex. The average half-lives of the antibiotic in the tissues of rats with TRI increase compared with the group of rats with NRF, though the difference are not so significant as in the case of the plasma half-life. The use of a specific kinetic distribution model, with linear and non-linear tissue binding, showed that significant variations occur in the partition coefficient and in the Michaelis-Menten parameters, which characterize the saturable binding of Amikacin to tissue in rats with NRF and TRI.     

Narrowband UVB therapy for vitiligo: does the repigmentation last?

BACKGROUND: Since 1997, a number of trials have shown promising results in treating generalized vitiligo with narrowband ultraviolet B (UVB) both in adults and children. However, there is little knowledge concerning the duration and permanency of the treatment-induced repigmentation. OBJECTIVE: Our main objective was to perform a follow-up trial of successfully treated patients receiving narrowband UVB for generalized vitiligo. METHODS: We have investigated to what degree the treatment-induced repigmentation remains stable for up to 2 years post-treatment. We performed an initial open trial including 31 patients with generalized vitiligo. They received narrowband UVB thrice weekly for up to 12 months. Patients experiencing > 75% repigmentation were defined responders and were included in the follow-up trial. Responders were followed every 6 months for up to 2 years after cessation of treatment. We observed the pigmentation status and registered any changes indicating loss of pigmentation and relapse. RESULTS: Eleven of the 31 treated patients were included in the follow-up trial. Six patients had relapse and five patients had stable response 24 months after cessation of treatment. Four out of six relapses were within 6 months post-treatment. CONCLUSION: In our study population of 31 patients with generalized vitiligo, five patients (16%) experienced > 75% stable repigmentation 2 years after cessation of a treatment programme of up to 1 years narrowband UVB therapy.     

Parvalbumin immunoreactive neurons and fibres in the teleost cerebellum

Summary The distribution of parvalbumin-(PV) immunopositive cell bodies and fibres in the cerebellum of two species of freshwater teleosts (Salmo gairdneri and Barbus meridonalis) was studied using a monoclonal antibody and the avidin-biotin immunoperoxidase technique. A clear laminated pattern of PV immunoreactivity was observed. After PV-immunostaining, Purkinje cells were strongly labelled in their cell bodies, the initial segments of the axons and the dendritic trees. In the molecular layer, only the dendritic branches of the Purkinje cells were PV-positive. In the granule cell layer, extensive axonal plexuses and scattered cell bodies were observed. Most of the immunopositive perikarya were unequivocally identified as displaced Purkinje cells, whereas a reduced number of smaller neurons with unstained dendrites was also found. Eurydendroid cells, the efferent neurons of the teleost cerebellum, were negative; however, they were impinged upon by numerous PV-positive boutons, corresponding to terminals of Purkinje cell axons. Parallel fibres and climbing fibres, as well as stellate cells and granule cells were negative. Basket cells (or deep stellate cells) whose existence in the teleost cerebellum is discussed, were also not observed. The immunoreactivity distribution pattern for PV in the teleost cerebellum differs from previous observations on the localization of this protein in the cerebellum of amniotes.