Interplay in lipoplexes between type of pDNA promoter and lipid composition determines transfection efficiency of human growth hormone in NIH3T3 cells in culture.

This study was aimed to investigate if and to what extent there is an interplay between lipoplex physicochemical properties and plasmid promoter type affecting transfection efficiency in vitro. To reduce the number of variables only one cell type (NIH3T3 cells), one gene (human growth hormone), one cationic lipid (DOTAP) in a plasmid >85% in supercoiled form, and the same medium conditions were used. The variables of the physicochemical properties included presence and type of helper lipid (DOPE, DOPC, or cholesterol, all in 1:1 mole ratio with DOTAP), size and lamellarity of the liposomes used for lipoplex preparation (large unilamellar vesicles, LUV, versus multilamellar vesicles, MLV), and DNA(-)/cationic lipid(+) charge ratio, all containing the same human growth hormone but differing in their promoter enhancer region. Two of the promoters were of viral origin: (a) SV40 promoter (simian virus early promoter) and (b) CMV promoter (cytomegalovirus early promoter); two were of mammalian cell origin: (c) PABP promoter (human poly(A)-binding protein promoter) and (d) S16 promoter (mouse ribosomal protein (rp) S16 promoter). Transfection studies showed that, irrespective of promoter type, large (> or =500 nm) MLV were superior to approximately 100 nm LUV; the extent of superiority was dependent on liposome lipid composition (larger for 100% DOTAP and DOTAP/DOPE than for DOTAP/DOPC and DOTAP/cholesterol). The optimal DNA(-)/DOTAP(+) charge ratio for all types of lipoplexes used was 0.2 or 0.5 (namely, when the lipoplexes were positively charged). Scoring the six best lipoplex formulations (out of 128 studied) revealed the following order: pCMV (DOTAP/DOPE) >> pSV (DOTAP/DOPE)=pCMV(DOTAP/cholesterol)=pS16 (100% DOTAP)=pS16 DOTAP/DOPE >> pCMV (DOTAP/DOPC). The lack of trivial consistency in the transfection efficiency score, the pattern of transfection efficiency, and statistical analysis of the data suggest that there is cross-talk between promoter type and lipoplex lipid composition, which may be related to the way the promoter is associated with the lipids.

The great tocolytic debate: some pitfalls in the study of safety.

The controversy surrounding the use of tocolytic agents has been raging for decades. Tocolytic drugs play a pivotal role in the prevention of preterm birth, which is the major cause of neonatal morbidity and mortality. Studies on the efficacy and safety of these drugs are of the utmost importance to many disciplines within the medical community. Unfortunately, many clinical decisions regarding tocolytic agents are based on incorrect information resulting from flawed studies. In this article we discuss the major design flaws common to many studies of tocolytic safety and in so doing explain some of the conflicting evidence regarding safety. Each of the two major types of study designs, preterm birth retrospective studies and prospective randomized trials, is associated with a serious flaw. Retrospective preterm birth studies give misleading and inconclusive results to the question of safety because of the use of incomplete cohorts. The inadequately sized prospective studies in the current literature lack the power to detect important clinical differences.

Effect of white noise "masking" on vestibular evoked potentials recorded using different stimulus modalities.

Short latency vestibular evoked potentials (VsEPs) to linear acceleration impulses (L-VsEPs) are initiated in the otolith organs (saccule and utricle). Some of the saccule afferents have been reported to respond not only to linear acceleration, but also to high intensity acoustic stimuli. If so, the L-VsEP recorded from the saccule (elicited with the stimulus orientated relative to the head so as to optimally activate the saccule, i.e. stimulus in the vertical plane, Z-VsEP) should be reduced during high intensity broad band noise (BBN) "masking". Conversely, the utricular afferents have been reported to be less auditory-sensitive. Therefore, an L-VsEP which is mainly utricular in origin (stimulus in the horizontal plane, X-VsEP) should be less affected by this noise "masking". This was investigated in rats by recording X-VsEPs and Z-VsEPs and angular VsEPs (A-VsEPs), originating in the lateral semi-circular canals, before, during and after exposure to short duration, high intensity (113 dB SPL) BBN. This intensity completely masked auditory nerve evoked responses. The Z-VsEP did appear to be slightly more affected by the noise "masking" than the X-VsEP, implying the presence of more auditory-sensitive elements in the saccule. The A-VsEP was also affected by the BBN. The overall effect was relatively small (on average, 10-25% depression of the first wave of the different VsEPs). The responses showed recovery 5 min later.

Comparison of topical nedocromil sodium and oral terfenadine for the treatment of seasonal allergic conjunctivitis.

This double-masked, comparative, multicenter study was conducted to assess the onset of action and tolerability of nedocromil sodium 2% ophthalmic solution BID, 60-mg terfenadine tablets BID, and placebo in the treatment of seasonal allergic conjunctivitis. Two hundred sixty-eight patients in whom seasonal allergic conjunctivitis was diagnosed were assigned to 1 of 3 groups and administered study medication for 4 weeks. Patients' mean age was 33 years (range, 12 to 68 years); 57.8% (155 of 268) were female. Demographic characteristics were similar in all 3 groups. Although all 3 groups showed improvement in ocular symptoms, nedocromil sodium was associated with a statistically significantly faster onset of action than was terfenadine or placebo (P = 0.038). During the study, 29 nedocromil sodium-treated patients (36.7%) achieved control of symptoms in < or =2 minutes, and 61 (77.2%) achieved control in < or =15 minutes. The corresponding numbers were 21 (24.7%) and 50 (58.8%) in the terfenadine group and 25 (29.1%) and 48 (55.8%) in the placebo group. The frequency of adverse events was low and similar between groups (nedocromil sodium, 26; terfenadine, 32; placebo, 32). No severe treatment-related adverse events were reported. In conclusion, nedocromil sodium had a significantly faster onset of action than did terfenadine or placebo.

Systemic activity of ivermectin on the human body louse (Anoplura: Pediculidae).

Eighty-one to 100% of nymphs and females of the human body louse (Pediculus humanus humanus) that fed artificially on blood containing 2.5-10 ng ivermectin/ml died. The mortality of nymphs and female lice fed on rabbits treated with 200 micrograms/kg ivermectin was very high during the first two to three days, then declined sharply, reaching the level of the controls on day six. Nymphs were more sensitive than females. The average number of eggs laid by surviving females and the percentage that hatched from those eggs were lower than in controls.