Evidence of biochemical hyperandrogenism in women: the limitations of serum testosterone quantitation

Hyperandrogenism in women is a common clinical scenario and is characterised by menstrual disturbance, hirsutism and infertility. Accurate measurement of serum testosterone is often used in these patients to diagnose polycystic ovary syndrome (PCOS) and to prompt further investigation in patients with suspected androgen-secreting tumours. Immunoassay methods are commonly used for serum testosterone quantitation, although the 'gold standard' reference method is mass spectrometry (MS), which is only available at certain tertiary centres. In this retrospective observational study, 57 female patients were investigated for possible hyperandrogenism. Biochemical testing for testosterone using an immunoassay was compared to an MS method. Correlation between the immunoassay and MS method was worse at lower testosterone concentrations, however overall, gave a reasonably strong correlation coefficient of 0.73. This study highlights the ongoing controversy over the most reliable test for hyperandrogenism in clinical practice. It is vital that clinicians are aware of the limitations of these methods and the clinical repercussions.

Use of high-intensity statin therapy with simvastatin 80 mg and atorvastatin 80 mg in primary care

AIMS

Cardiovascular disease (CVD) is the most common cause of death worldwide. Pharmaceutical risk reduction with high-intensity statin therapy is advisable for high-risk patients. Clinicians face a conflict between prescribing for cost (simvastatin 80 mg) or for efficacy (atorvastatin 80 mg). The aim of this audit was to examine the use, efficacy and tolerability of high intensity statin treatment (simvastatin 80 mg; atorvastatin 80 mg) in primary care.

METHODOLOGY

Electronic medical records were examined from two general practitioners' surgeries. Analyses involved Mann-Whitney U and χ(2) tests.

RESULTS

A total of 116 patients had taken simvastatin 80 mg or atorvastatin 80 mg. Patients were similar between treatment groups: mostly men (62.9%), over 60 years old (68.1%), non-smokers (81.0%) taking statins for secondary prevention (56.9%). More patients on simvastatin withdrew from treatment as a result of inefficacy (49.3% vs. 23.2%, p=0.025) compared with the atorvastatin group. Furthermore, patients on simvastatin were more likely to be failing conventional targets of lipid control, compared with patients on atorvastatin 80 mg (43.5% vs. 21.3%, p=0.006). Tolerability was similar between the two groups.

DISCUSSION

UK guidelines recommend simvastatin 80 mg as an economic choice, despite scant evidence at this dose and recent safety concerns. Conversely, robust evidence exists for atorvastatin 80 mg. Head-to-head clinical trials or clinical studies comparing these agents are lacking. The present study suggests that atorvastatin 80 mg compares favourably to simvastatin in terms of efficacy and has a similar tolerability profile.

CONCLUSION

This retrospective observational study suggests that despite national guidelines, atorvastatin 80 mg is used in clinical practice and is more effective and at least as well tolerated as simvastatin 80 mg.

Efficacy of VectoLex WDG against Anopheles quadrimaculatus and Psorophora columbiae larvae in Arkansas and Mississippi rice

In 1999, an aerial application of VectoLex WDG (water-dispersible granules) at 1.68 and 0.56 kg/ha, applied against sentinel 3rd-stage larvae of Psorophora columbiae installed in 0.42-ha rice plots 48 h after treatment, provided no control at 72 and 96 h after treatment. Less than 10% reduction was obtained at both rates 8 and 9 days after treatment against larvae of Ps. columbiae installed at 7 days after treatment. In a later test, VectoLex WDG manually applied at 5.04 and 1.68 kg/ha to small rice plots containing sentinel 3rd-stage larvae of Ps. columbiae and Anopheles quadrimaculatus obtained 90 and 97% control of Ps. columbiae at both rates, respectively, 24 h after treatment. A 2nd installation of Ps. columbiae at 24 h after treatment resulted in 7% and no control at both rates, respectively, even in the presence of larval carcasses from the 1st installation. VectoLex WDG was not effective against Ps. columbiae after 24 h atter treatment at either rate. Poor control was obtained at both rates against An. quadrimaculatus 24 h and 48 h after treatment for both installations. Two types of commercial rice fields containing native populations of larvae of An. quadrimaculatus were used for field tests in Cleveland, MS. In 1999, VectoLex WDG, aerially applied at 1.68 and 0.56 kg/ha to 0.2-ha plots in a contoured rice field, produced 81 and 85% reductions in early (neonate and 1st- and 2nd-stage) larvae and 94 and 76% reductions in late (3rd- and 4th-stage) larvae 2 days after treatment, respectively. At 2 days after treatment, means for all 4 developmental groupings (early larvae, late larvae, pupae, and combined stages) were significantly higher in untreated plots. Both VectoLex WDG rates did not differ significantly from one another. At 8 days after treatment, untreated plots contained significantly greater mean numbers of early larvae, late larvae, and combined stages, whereas both VectoLex WDG treatments were not significantly different. In 2000, VectoLex WDG applied at 1.68 kg/ha to two 0.40-ha plots in a precision-leveled field yielded 59 and 100% reductions of early and late larvae, respectively, 2 days after treatment. Reduction of late larvae remained 100% at 8 days after treatment. The numbers of late larvae, pupae, and combined stages were significantly greater in the untreated plot 2 days after treatment. At 8 days after treatment, numbers of early larvae and combined stages were significantly higher in the VectoLex WDG plot, whereas numbers of late larvae were significantly higher in the untreated plot. The differences in susceptibility of Ps. columbiae and An. quadrimaculatus to VectoLex WDG could be attributed to species differences in larval feeding behavior, body positioning in the water column, and developmental time. In tests in Arkansas, Ps. columbiae were controlled more quickly, usually within 24 h of exposure, whereas the percent reduction for An. quadrimaculatus in both tests in Cleveland, MS, suggests that control of this species within the region tested required from 48 h up to 8 days of exposure.

Efficacy of Dibrom, Trumpet, and Scourge against four mosquito species in Louisiana

Adult mortality of Anopheles quadrimaculatus, Culex quinquefasciatus, and the Aedes spp. complex (Aedes sollicitans and Aedes taeniorhynchus) was observed after aerial ultra-low volume (ULV) exposure to Dibrom, Trumpet, and Scourge. Dibrom was applied at 112 g active ingredient (AI)/ha, Trumpet at 112 g AI/ha, and Scourge at 1.96 g AI/ha. At all time intervals, Dibrom and Trumpet were significantly more effective against the Aedes spp. complex than against An. quadrimaculatus and Cx. quinquefasciatus. Scourge was significantly more effective against An. quadrimaculatus and Cx. quinquefasciatus than Dibrom or Trumpet. Trumpet was evaluated at lower labeled rates (28, 56, and 84 g AI/ha) against Cx. quinquefasciatus and the Aedes spp. complex. Adult mortality with Trumpet increased significantly at 1 and 24 h against Cx. quinquefasciatus. With the Aedes spp. complex, mortality increased with rate at 1 h, but at 12 and 24 h, the medium and high dosages were not significantly different from each other. Culex quinquefasciatus and the Aedes spp. complex were also subjected to ULV ground applications of Dibrom, Trumpet, and Scourge. Dibrom was applied at 22.4 g AI/ha, Trumpet at 22.4 g AI/ha, and Scourge as a 1:6 mineral oil mixture at 1.96 g AI/ha. Relative to Dibrom and Trumpet, mortality from Scourge differed greatly with mosquito species. Against Cx. quinquefasciatus, Scourge was significantly more effective than Dibrom and Trumpet at all times and distances, but against the Aedes spp. complex Scourge was significantly less effective.

Polymerase chain reaction assay to identify all immature stages of two species of the Anopheles quadrimaculatus sibling species complex (Diptera: Culicidae)

A polymerase chain reaction assay that detects differences in the 2nd internal transcribed spacer of ribosomal DNA was tested as a means to identify all immature stages of 2 species in the Anopheles quadrimaculatus sibling species complex. The technique was successful in amplifying DNA from eggs, 1st-4th instars, and pupae of An. quadrilmaculatus Say and An. inundatus Reinert.

Mosquito (Diptera: Culicidae) host compatibility and vector competency for the human myositic parasite Trachipleistophora hominis (Phylum Microspora)

Microsporidian spores of Trachipleistophora hominis Hollister, isolated from a human, readily infected larval stages of both Anopheles quadrimaculatus Say sensu lato and Culex quinque-fasciatus Say. Mosquito infections with T. hominis were located, primarily, in abdominal muscles in segment numbers 4 through 6; other spores were found in the hemocoel and proboscis. Nearly 50% of the infected mosquito larvae survived to the adult stage. Spores recovered from adult mosquitoes were inoculated into mice and resulted in significant muscle infection at the site of injection. Preliminary observations also showed that T. hominis spores can be passively transferred from infected mosquitoes to a sugar water substrate.

Field trial efficacy of two formulations of Permanone against Culex quinquefasciatus and Anopheles quadrimaculatus

Tests were conducted during the summer of 1996 to evaluate the effectiveness of different formulations of permethrin, Permanone 31-66 and Aquareslin, against Anopheles quadrimaculatus and Culex quinquefasciatus. Tests of both formulations were conducted at rates of 2.019 and 3.926 g AI/h with each formulation/rate replicated 3 times. Results indicate significantly greater control of both pest species at the higher application rate for both formulations. The high rate of Permanone 31-66 proved more effective than that of Aquareslin. Exposure at the low rate for both formulations provided inadequate adult control that was particularly pronounced against Cx. quinquefasciatus. Regardless, negligible recovery of exposed adults was observed at any formulations/rate. No significant differences in mortality were noted for any formulation/rate relative to distance downwind. However, volume median diameter and droplets/cm2 were significantly affected by distance downwind. Furthermore, volume median diameter and droplets/cm2 were both determined to significantly affect mortality in both mosquito species (P < or = 0.05). Overall, results indicate that Permanone 31-66 and Aquareslin applied at a rate of 3.926 g AI/h were effective.

Efficacy of three synthetic pyrethroids against three mosquito species in Arkansas and Louisiana

Adult mortality of Anopheles quadrimaculatus, Culex quinquefasciatus, and Aedes sollicitans was observed following ultra-low-volume (ULV) exposure to Responde, Permanone 31-66 RTU, and Scourge. Permanone 31-66 RTU (1:2.13, permethrin:PBO) and Scourge (1:3, resmethrin:PBO) were applied at 0.00175 lb AI/acre, while Responde (1:3, prallethrin:PBO) was applied at 0.001 lb AI/acre, and all were evaluated at 100, 200, and 300 ft. downwind of application. Significant mortality differences (P < or = 0.05) were observed among all compounds at 15 min and at 1, 12, and 24 h posttreatment against An. quadrimaculatus and Cx. quinquefasciatus. Responde exhibited significantly greater (P < or = 0.05) control (knockdown) against An. quadrimaculatus at both 15 min and 1 h posttreatment than did Permanone 31-66 RTU or Scourge; however, some recovery occurred by 12 h posttreatment. At 15 min posttreatment, Responde and Scourge were significantly (P < or = 0.05) more effective against Cx. quinquefasciatus than Permanone 31-66 RTU except at 300 ft. downwind, where Scourge was significantly (P < or = 0.05) more effective than either compound. No significant mortality differences (P < or = 0.05) were observed among the 3 compounds at 15 min, 1 h, 12 h, and 24 h posttreatment when tested against Ae. sollicitans. No significant mortality differences (P < or = 0.05) were observed between the 1:3 and 1:5 (prallethrin: piperonyl butoxide) formulations of Responde at any time posttreatment when tested against Ae. sollicitans.

Validation of a ribosomal DNA-polymerase chain reaction species diagnostic assay for the common malaria mosquito (Diptera:Culicidae) sibling species complex

A polymerase chain reaction method for identifying individuals in the Anopheles quadrimaculatus Say sibling species complex was validated for wild mosquitoes from Louisiana and Mississippi. This method distinguished An. quadrimaculatus species A, B, C, and D by detecting species-specific differences in the 2nd internal transcribed spacer of ribosomal DNA and was 100% specific and 95% sensitive.

Dispersal and distribution of Calliphoridae (Diptera) immatures from animal carcasses in southern Louisiana

Spatial distributions of calliphorid pupae (based on adult emergence) from swine carcasses located in woods and pasture were determined during 4 seasons in southern Louisiana. Adult emergence was substantially greater in pastures than woods for all seasons except winter. Secondary screwworm, Cochliomyia macellaria (F.), was the predominant calliphorid species collected ( > 95%) during summer and fall; whereas, black blow fly, Phormia regina (Meigen), was the primary species (86%) during spring. The highest densities of calliphorid pupae per square meter were located within 0.9 m of the animal carcasses in the woods and the pasture (summer); however, the number of calliphorid pupae per square meter during the summer was substantially greater in the pastures than in the woods (2,370/m2 compared with 77/m2). Postfeeding calliphorid larvae preferred to disperse toward the southeastern quadrant during summer and spring and toward the southeastern to southwestern quadrants in fall. The winter evaluation period was the most prolonged (85 d), had the least number of emergent adults (only 6-11% of the populations that emerged in the other seasons), and consisted of predominantly, Phaenicia sericata (Meigen).

Record of Anopheles quadrimaculatus species C in Louisiana

Sibling species C of the Anopheles quadrimaculatus species complex was found south of Abbeville (Vermilion Parish), Louisiana, during a state-wide survey in 1993. This constitutes a new state record and currently represents its westernmost distribution.

Evaluation of aerial and ground-applied adulticides against mosquito species in Arkansas and Louisiana

Mosquitoes were subjected to ultra-low volume (ULV) aerial applications of permethrin synergized with piperonyl butoxide (Biomist 30:30. Biomist 31:66) and Cythion and ULV ground applications of permethrin synergized with piperonyl butoxide (Biomist 30:30. Biomist 12:60), resmethrin (Scourge), and sumithrin (Solo 40-OS and Duets 8.8-OS). Permethrin compounds tested aerially against Anopheles quadrimaculatus were not significantly different. Biomist 30:30 tested aerially against Culex quinquefasciatus did provide significantly greater mortality compared to Cythion. Biomist 30:30 and Biomist 31:66 tested aerially against An. quadrimaculatus at 1 h did not provide a significant difference up to 600 ft. (182.9 m). Both products ground tested at 24 h revealed nonsignificant results. Biomist 30:30 and Biomist 12:60 ground tested against Cx. quinquefasciatus at 1 h did not provide a significant difference at 100 ft. (30.5 m) or 200 ft. (61.0 m); however, significantly greater mortality was observed at 300 ft. (61.0 m) and 600 ft. (91.4 m). At 24 h no significant mortality differences were observed at 300 ft. (61.0 m) and 600 ft. (91.4 m). Anopheles quadrimaculatus and Psorophora columbiae were treated with a 1:1 mixture of Solo 40-OS and Duet 8.8-OS (sumithrin+piperonyl butoxide). Significant mortality differences (P < or = 0.05) between species at 1 h posttreatment occurred at 300 ft. (91.4 m).

Effects of ivermectin in canine blood on Anopheles quadrimaculatus, Aedes albopictus and Culex salinarius

Blood from ivermectin-treated dogs was tested against adult mosquitoes. Mosquitoes were allowed to bloodfeed on mixed breed dogs 4 h after dogs were given oral dosages of ivermectin. In test 1, Anopheles quadrimaculatus and Aedes albopictus fed on dogs that had been given ivermectin dosages of 0, 6, 12, and 24 micrograms/kg. In test 2, Culex salinarius and Ae. albopictus fed on dogs that had been given dosages of 0, 15, 30, 60, and 120 micrograms/kg. In both tests, mosquitoes were observed for mortality at 1, 12, and 24 h postfeeding. Surviving mosquitoes were observed for oviposition and egg hatching. In the first test, there was a significant increase in mortality and a significant decrease in number of eggs/female and egg hatchability in An. quadrimaculatus but not in Ae. albopictus (P < 0.05). An LD50 of 9.9 micrograms/kg (95% FL 6.0-13.8) was determined for An. quadrimaculatus. In the 2nd test, there were no significant differences in any variable for Cx. salinarius or Ae. albopictus, except that eggs from Ae. albopictus had reduced hatching at all dosages.

Susceptibility of Psorophora columbiae Larvae over Time to Parasitism by Romanomermis culicivorax

The ability of Romanomermis culicivorax preparasites to penetrate and infect Psorophora columbiae decreased substantially after ca. 28 hours. Parasitism at temperatures typical of Louisiana rice fields (i.e., 26, 29, and 32 +/- 0.5 C) showed a significant linear decrease (P < 0.01) as the percentage of older larval instars increased at the times of exposure. These data emphasize the need for a synchronous field application of preparasites to challenge the rapid development of early instars of Ps. columbiae. Applications of postparasites rather than insecticide treatments to potential mosquito breeding habitats may offer greater flexibility in larval mosquito control programs.