Properties of the tick-borne encephalitis virus population during persistent infection of ixodid ticks and tick cell lines.

Tick-borne encephalitis virus (TBEV) is the causative agent of tick-borne encephalitis (TBE), a vector-borne zoonotic neuroinfection. For successful circulation in natural foci the virus has to survive in the vector for a long period of time. Information about the effect of long-term infection of ticks on properties of the viral population is of great importance. In recent years, changes in the eco-epidemiology of TBEV due to changes in distribution of ixodid ticks have been observed. These changes in TBEV-endemic areas could result in a shift of the main tick vector species, which in turn may lead to changes in properties of the virus. In the present study we evaluated the selective pressure on the TBEV population during persistent infection of various species of ticks and tick cell lines. TBEV effectively replicated and formed persistent infection in ticks and tick cell lines of the vector species (Ixodes spp.), potential vectors (Dermacentor spp.) and non-vector ticks (Hyalomma spp.). During TBEV persistence in Ixodes and Dermacentor ticks, properties of the viral population remained virtually unchanged. In contrast, persistent TBEV infection of tick cell lines from both vector and non-vector ticks favoured selection of viral variants with low neuroinvasiveness for laboratory mice and substitutions in the E protein that increased local positive charge of the virion. Thus, selective pressure on viral population may differ in ticks and tick cell lines during persistent infection. Nevertheless, virus variants with properties of the original strain adapted to mouse CNS were not eliminated from the viral population during long-term persistence of TBEV in ticks and tick cell lines.

A multiple-baseline, double-blind evaluation of the effects of trimeprazine tartrate on infant sleep disturbance.

Infant sleep disturbance involving chronic night waking and resistance to settling to sleep or returning to sleep is a common problem for families with children 6-27 months old. Prescription and nonprescription sedatives are frequently administered without clear evidence that they are effective as either long-term or short-term palliatives. Trimeprazine tartrate, administered either 15 mg/5 mL or 30 mg/5 mL, was compared with both baseline and placebo in a multiple-baseline-across participants, double-blind study. No clinically significant effects of the low dose were detected, whereas the effects of the high dose were not consistently replicated across nor within participants. During active drug treatment, only 2 of 12 children achieved Sleep Behaviour Scale scores indicative of nonproblem sleep. Trimeprazine tartrate is not recommended as a pharmacological treatment for infant sleep disturbance unless as an adjunct to a behavioral therapy program.

Studies on antimicrobial effect of the antihistaminic phenothiazine trimeprazine tartrate.

The antibacterial and bactericidal activities of the antihistamine trimeprazine were studied against 243 strains of bacteria which included both Gram positive and Gram negative types. The susceptibility of these bacterial strains to trimeprazine was assessed by determining their minimum inhibitory concentration (MIC) which was found to be between 10 and 100 micrograms/ml. Nineteen strains of Staphylococcus spp. and Salmonella spp. were trimeprazine. Most of the strains belonging to Bacillus spp. and Salmonella spp. were inhibited by less than 100 micrograms/ml. Trimeprazine could also inhibit strains of Shigella spp. Vibrio cholerae and V. parahaemolyticus at 10-100 micrograms/ml. Strains of klebsiella, proteus, pseudomonas and citrobacter were moderately sensitive to trimeprazine. In in vivo studies it was seen that when trimeprazine was used at a concentration of 0.75 and 0.4 micrograms/gm body weight of the mouse both levels offered significant protection to Swiss mice challenged with 50LD50 of virulent strain of S. typhimurium 74. Statistical analysis of the data was found to be significant, p < 0.001 according to chi 2 test.

Behavioural changes in children following minor surgery--is premedication beneficial?

One hundred and twenty-three male children, aged one to ten years, were studied to determine the influence of premedication on changes in patterns of behaviour following hospitalization for repair of inguinal hernias. Four comparable groups were selected for premedication regimen: (1) A control group without premedication; (2) oral trimeprazine tartrate 2 mg/kg, methadone 0.1 mg/kg and droperidol 0.15 mg/kg; (3) oral midazolam 0.45 mg/kg; (4) intramuscular midazolam 0.15 mg/kg. Standard inhalational anesthesia was used and caudal blocks employed for analgesia. The parents returned a questionnaire at two weeks. Changes in behaviour were reported in 78% of the children and overall, premedication showed little benefit. However, midazolam premedication was associated with a significantly lower incidence of night-time crying and awakening, compared with no premedication. Only for night-time crying and day-time toilet training did age below five years prove to be a significant contributing factor.

A double-blind drug trial of treatment in young children with waking problems.

A double-blind trial using trimeprazine tartrate was carried out in 22 children with severe waking problems. On parental verbal reports sleep was significantly improved on the drug compared with the original baseline and the placebo, but diaries kept by the parents showed that this improvement was clinically only moderate, with many wakeful nights still occurring. Taking the drug produced no permanent effect on sleep patterns and a follow-up of 14 children 6 months later showed persisting sleep problems in the majority.