Pyrethroid pediculicide resistance of head lice in Canada evaluated by serial invasive signal amplification reaction.

BACKGROUND: Most people in the United States and Canada with pediculosis will be treated with neurotoxic pediculicides containing pyrethrins or pyrethroids. Their widespread use led to significant resistance reported from various countries. Although treatment failures are frequently observed in Canada, the resistance frequency to pyrethroid pediculicide of human head lice (Pediculus humanus capitis) has not been determined. OBJECTIVE: To determine the knockdown resistance (kdr) allele frequency in human head louse populations in Canada. METHODS: Patients infested with Pediculus humanus capitis, aged 4 to 65 years, residents of Ontario, Quebec, and British Columbia, were participants. Head lice were collected by combing and picking the enrolled subjects' hair. Lice were analyzed by serial invasive signal amplification reaction (SISAR) for genotyping the T917I mutation of lice indicating permethrin resistance. The permethrin-resistant kdr allele (R allele) frequency could then be evaluated in the head lice collected in Canada. RESULTS: Of the head louse populations analyzed, 133 of 137 (97.1%) had a resistant (R) allele frequency, whereas only 4 of 137 (2.9%) had a susceptible (S) allele frequency. CONCLUSIONS: The 97.1% resistant (R) allele frequency in head lice from Canada could explain the treatment failures encountered with pyrethrin and pyrethroid pediculicide treatments in Canadian populations infested with Pediculus humanus capitis as the latter will not be eliminated by those pediculicides.

A comparison of fish oil, flaxseed oil and hempseed oil supplementation on selected parameters of cardiovascular health in healthy volunteers.

OBJECTIVE: The impact of dietary polyunsaturated fatty acids (PUFAs) of the n-6 and n-3 series on the cardiovascular system is well documented. To directly compare the effects of three dietary oils (fish, flaxseed and hempseed) given in concentrations expected to be self-administered in the general population on specific cardiovascular parameters in healthy volunteers. DESIGN: 86 healthy male and female volunteers completed a 12 week double blinded, placebo controlled, clinical trial. They were randomly assigned to one of the four groups. Subjects were orally supplemented with two 1 gm capsules of placebo, fish oil, flaxseed oil or hempseed oil per day for 12 weeks. RESULTS: Plasma levels of the n-3 fatty acids docosahexanoic acid and eicosapentanoic acid increased after 3 months supplementation with fish oil. Alpha linolenic acid concentrations increased transiently after flaxseed supplementation. However, supplementation with hempseed oil did not significantly alter the concentration of any plasma fatty acid. The lipid parameters (TC, HDL-C, LDL-C and TG) did not show any significant differences among the four groups. Oxidative modification of LDL showed no increase in lag time over the 12 wk period. None of the dietary interventions induced any significant change in collagen or thrombin stimulated platelet aggregation and no increase in the level of inflammatory markers was observed. CONCLUSION: From a consumer's perspective, ingesting 2 capsules of any of these oils in an attempt to achieve cardiovascular health benefits may not provide the desired or expected result over a 3 month period.

North American efficacy and safety of a novel pediculicide rinse, isopropyl myristate 50% (Resultz).

BACKGROUND: Head lice infestations are a major nuisance in school-aged children and are a worldwide public health problem. There are growing concerns about the effectiveness of current treatments owing to increasing resistance, safety, and patient noncompliance. A safe, easy to use, effective alternative is needed. OBJECTIVE: A pediculicide rinse, 50% isopropyl myristate (IPM), was assessed in two phase 2 trials conducted in North America. The first trial was a nonrandomized (proof of concept) trial without a comparator conducted in Winnipeg, Canada. The second trial, conducted in the United States, was an evaluator-blinded, randomized superiority trial comparing 50% IPM rinse with a positive control (RID; pyrethrin 0.33%, piperonyl butoxide 4%). The primary end points were to determine the safety and efficacy of 50% IPM as a pediculicide rinse. METHODS: Subjects meeting inclusion criteria were enrolled in the above-mentioned trials with efficacy end points 7 and 14 days post-treatment. Subjects were also evaluated on days 0, 7, 14, and 21 for the presence of erythema and edema using the Modified Draize Scale. Other comments associated with the safety evaluation (ie, pruritus) were collected. RESULTS: IPM was found to be effective in the proof of concept study and comparator trial using a positive control. IPM was also well tolerated, with minimal adverse events. All adverse events were mild, resolving by completion of the study. CONCLUSION: Data suggest that IPM is a safe and effective therapy for the treatment of head lice in children and adults. IPM's mechanical mechanism of action makes development of lice resistance unlikely.

The differences in human cumulative irritation responses to positive and negative irritant controls from three geographical locations.

A retrospective analysis was conducted to evaluate whether studies from three geographically diverse locations have similar response profiles to the positive and negative controls in a standard 14-day cumulative irritation study (1). The positive irritant control (0.1% sodium lauryl sulfate, SLS) and the negative control (0.9% sodium chloride, saline) data from seventeen 14-day cumulative irritation studies were reviewed. The studies were compiled from three locations representing dry/hot, humid/hot, and dry/cold environments (Scottsdale, Arizona; St. Petersburg, Florida; and Winnipeg, Manitoba, respectively). Irritation scores were generated by trained skin graders from a total of 442 subjects studied between 1999 and 2005. Cumulative irritation scores were reviewed and compared between study locations. The irritation scores for the positive and negative controls were not significantly different between locations. Temperature and relative humidity (RH) variation did not correlate significantly with overall irritation. However, the dryer climate (i.e., negative or low dew point) had a tendency to induce a higher overall irritation level for both positive and negative controls.

Supplementation with omega3 polyunsaturated fatty acids and all-rac alpha-tocopherol alone and in combination failed to exert an anti-inflammatory effect in human volunteers.

There is growing evidence supporting the importance of inflammation in all stages of atherosclerosis. While both omega-3 polyunsaturated fatty acids (n3PUFA) and the lipid-soluble antioxidant alpha-tocopherol (AT) have been shown to independently have significant anti-inflammatory effects, there is paucity of data examining the effect of n3PUFA alone and in combination with AT on markers of inflammation and monocyte function. Therefore, we tested the effect of n3PUFA alone, all-rac (synthetic) AT alone, and the combination on markers of inflammation and monocyte function. Healthy nonsmoking volunteers were randomly assigned to 1 of 4 groups (n = 20 per group): 1.5 g/d n3PUFA, 800 IU/d AT, 1.5 g n3PUFA + 800 IU/d AT, or placebo in a parallel double-blinded study. Compared to baseline, 12 weeks of supplementation resulted in no changes in plasma lipids regardless of treatment. Plasma AT was significantly increased only in those groups that received AT (P <.0001). Similarly, groups receiving n3PUFA showed a significant increase in plasma docosahexaenoic acid (P <.0001). No significant within- or between-group differences were found for plasma levels of high-sensitivity C-reactive protein (hsCRP). Furthermore, there were no differences in monocyte proinflammatory cytokine release (interleukin [IL]-1beta, tumor necrosis factor [TNF]-alpha and IL-6) after activation with monocyte chemotactic protein-1 (MCP-1). In conclusion, supplementation with n3PUFA and all-rac AT at these doses is not anti-inflammatory.

Supplementation with a pine bark extract rich in polyphenols increases plasma antioxidant capacity and alters the plasma lipoprotein profile.

Pycnogenol (PYC), an extract of French maritime pine bark (Pinus pinaster), is a potent antioxidant with potential health benefits. Its bioavailabilty has previously been shown by urinary excretion studies of constituents and metabolites of PYC. The aim of this study was to test the effect of PYC supplementation on measures of oxidative stress and the lipid profile in humans. Twenty-five healthy subjects received PYC (150 mg/d) for 6 wk. Fasting blood was collected at baseline, after 3 and 6 wk of supplementation, and again after a 4-wk washout period. After 6 wk of supplementation with PYC, a significant increase in plasma polyphenol levels was detectable, which was reversed after the 4-wk washout phase. The antioxidant effect of PYC was demonstrated by a significant increase in oxygen radical absorbance capacity (ORAC) in plasma throughout the supplementation period (P < 0.05). The ORAC value returned to baseline after the 4-wk washout period. Moreover, in addition to its antioxidant effects, PYC significantly reduced LDL-cholesterol levels and increased HDL-cholesterol levels in plasma of two-thirds of the subjects. While the LDL changes reversed during washout, the HDL increase did not. There was no significant difference in LDL oxidizability or plasma lipid peroxides following PYC supplementation. Hence, following oral supplementation in humans, PYC significantly increases antioxidant capacity of plasma, as determined by ORAC, and exerts favorable effects on the lipid profile.