The association between sympatho-vagal balance and central blood pressures.

PURPOSE: High central blood pressure is more predictive of cardiovascular disease (CVD) versus high peripheral blood pressure. Measures of central pressures (CPs) include, central systolic blood pressure (CSBP) and central diastolic blood pressure. Measures of central pressures augmentation (CPsA) include augmentation pressure (AP) and the augmentation index @ 75 beats·min-1 (AIx@75). Increased sympathetic tone (ST) is also associated with CVD. The low to high frequency ratio (LF/HF) is often used to determine sympatho-vagal balance. Given the association between ST, CPs, CPsA and CVD there is a need to understand the association between these predictors of CVD. The aims of this study were to examine the association between the LF/HF ratio, CPs, and CPsA in men and women collectively and based on gender. METHODS: We measured the LF/HF ratio, CSBP, AP, and AIx@75 in 102 participants (41F/61M). The LF/HF ratio was determined via power spectral density analysis. CSBP, AP, and AIx@75 were determined via applanation tonometry. RESULTS: The LF/HF ratio was inversely associated with AP (r = -0.26) and AIx @75 (r = -0.29) in the combined group of men and women. The LF/HF ratio was inversely associated with CSBP (r = -0.27), AP (r = -0.28), and AIx@75 (r = -0.32) in men, but not in women. CONCLUSION: There is an inverse association between the LF/HF ratio, AP, and AIx@75 in men and women combined. The association between the LF/HF ratio, CSBP, AP, and AIx@75, differs based on gender.

Cognitive Performance Does not Limit Physical Activity Participation in the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P).

OBJECTIVES: We examined whether multiple domains of baseline cognitive performance were associated with prospective physical activity (PA) adherence in the Lifestyle Interventions and Independence for Elders Pilot study (LIFE-P). DESIGN, SETTING, PARTICIPANTS: The LIFE-P study was a single-blind, multicenter, randomized controlled trial of a PA intervention compared to a successful aging educational intervention in sedentary, mobility-limited older adults. INTERVENTION: A 12-month structured, moderate-intensity, multi-modal PA program that included walking, resistance training, and flexibility exercises. For the first 2 months (adoption), 3 center-based exercise sessions (40-60 min) / week were conducted. During the next 4 months (transition), center-based sessions were conducted 2 times / week. The subsequent maintenance phase consisted of optional once-to-twice-per-week center-based sessions and home-based PA. MEASUREMENTS: Tests of executive and global cognitive functioning, working memory and psychomotor speed were administered at baseline. Median test scores were used to dichotomize participants into low or high cognitive performance groups. RESULTS: 52 mobility-limited older adults (age: 76.9 ±5 yrs) were randomized to the PA arm of LIFE-P. Compared to participants with high cognitive performance, participants with low performance had similar PA adherence rates (all P ≥ 0.34). Furthermore, weak and non-significant univariate relationships were elicited between all measures of cognition and overall PA adherence levels (r values ranged: -0.20 to 0.12, P ≥ 0.12). CONCLUSION: These data suggest that cognitive performance does not limit long-term PA adherence in mobility-limited older adults. Additional studies in larger cohorts are warranted to verify these findings.

Serum IL-17F does not predict poor response to IM IFNß-1a in relapsing-remitting MS.

OBJECTIVE: There is a significant unmet need for serum biomarkers in relapsing-remitting multiple sclerosis (RRMS) that are predictive of therapeutic response to disease-modifying therapies. Following a recent Stanford study which reported that pretreatment levels of serum interleukin (IL)-17F could predict poor response to interferon-ß (IFNß) therapy, we sought to validate the finding using samples from a large clinical trial. METHODS: The validation cohort included 54 good responders (GR) and 64 poor responders (PR) selected from 762 subjects with RRMS from the IM IFNß-1a dose comparison study (Avonex study C94-805). Subjects were classified as GR and PR based on the number of relapses, Expanded Disability Status Scale score, and new and enlarging T2 lesions on MRI. Serum samples were assayed for IL-17F using a multiplexed Luminex assay and for IL-17F/F using an ELISA. Replicate aliquots from the Stanford study were also assayed to assure reproducibility of methods. RESULTS: Median pretreatment and post-treatment serum IL-17F levels were not statistically significantly different between GR and PR, and serum IL-7/IL-17F ratios were also not predictive of response status. Replicate aliquots from the Stanford study showed good correlation to their original cohort (r = 0.77). CONCLUSIONS: We were unable to validate the finding that serum IL-17F is a predictor of PR in a large independent cohort of subjects with RRMS. Differences in patient populations and methodology might explain the failure to validate the results from the Stanford study.

Blastomyces dermatitidis lysate antigens: antibody detection in serial serum specimens from dogs with blastomycosis.

Yeast phase lysate antigens prepared from different isolates of Blastomyces dermatitidis (T-58, dog-Tennessee; T-27, polar bear-Tennessee; ERC-2, dog-Wisconsin; ER-3, woodpile-Wisconsin) were compared with respect to the detection of antibodies (indirect enzyme-linked immunosorbent assay-ELISA, peroxidase system) in 126 serial serum specimens (pre-treatment, 30 and 60 days post-treatment with itraconazole) from 42 dogs with diagnosed blastomycosis. Mean absorbance values observed with the four lysate antigens at the three treatment intervals ranged from the most reactive to the least reactive as follows: T-58 (0.270, 0.210, 0.136); T-27 (0.209, 0.156, 0.096); ER-3 (0.189, 0.144, 0.089) and ERC-2 (0.158, 0.129, 0.080). Even though variations in reactivity were evidenced, the lysates prepared from isolates from various geographical regions and sources were all efficacious as antigens for the immunodiagnosis of canine blastomycosis.

Serological differences in three Blastomyces dermatitidis strains.

Yeast phase lysate antigens, prepared from three isolates of Blastomyces dermatitidis (T-58, Tennessee dog; 48089, Zaire human; ERC-2, Wisconsin dog) were assayed for their ability to detect antibodies in human sera, dog sera and sera from rabbits immunized with each of the lysate antigens. The dog sera were from animals diagnosed with blastomycosis from various endemic regions in North America. T-58 and ERC-2 lysate antigens exhibited a high reactivity with the serum from dogs infected with blastomycosis; however, 48089 lysate showed low reactivity with the same sera. With the immunized rabbit sera, 48089 lysate was the only lysate with a high reactivity with the 48089 serum and it exhibited little reactivity with the heterologous sera. The T-58 and ERC-2 lysate antigens reacted minimally with the 48089 serum but reacted highly with both the T-58 and ERC-2 sera. The human sera were from individuals potentially exposed to B. dermatitidis while working on a prairie dog relocation project in Colorado. Remarkably, all three lysate antigens could detect antibodies in the individuals diagnosed with blastomycosis. This study indicated that there were serological differences in the 48089 Zaire lysate compared with the other lysate antigens and it may be designated serotype 2.

Serological differences in two Blastomyces dermatitidis isolates from different geographical regions of North America.

Yeast phase lysate antigens were prepared from two isolates (T-58 and ERC-2) from different geographic locations. Tennessee and Wisconsin. These lysate were evaluated with respect to their ability to detect antibody in dogs infected with blastomycosis and rabbits immunized with the lysates by an enzyme linked immunosorbent assay (ELISA). Both the dog sera and rabbit sera assays demonstrated that there were serological differences in these two isolates, which implied that there was antigenic variance in geographical populations of B. dermatitidis. These results correlated with a previous molecular study that indicated that there are genetic differences in different geographical populations of the organism.

Comparison of seven Blastomyces dermatitidis antigens for the detection of antibodies in humans with occupationally acquired blastomycosis.

Yeast phase lysate antigens, prepared from seven isolates of Blastomyces dermatitidis (dogs, T-58, M-98; human, Le; soil, S; sea lion, SL; polar bear, PB; cat, C) were assayed by enzyme-linked immunosorbent assay (ELISA) to detect antibodies in human sera. The sera were from individuals potentially exposed to B. dermatitidis while working on a prairie dog relocation project in Colorado. All antigens exhibited greatest reactivity with three specimens in two separate assays. Absorbance values ranged from 0.370 (M-98) to 0.427 (LE) (Trial 1) and from 0.579 (M-98) to 0.714 (PB) (Trial 2) with serum 2; from 0.368 (C) to 0.453 (LE) (Trial 1) and from 0.565 (SL) to 0.694 (S) (Trial 2) with serum 3 and from 0.392 (M-98) to 0.506 (LE) (Trial 1) and from 0.557 (SL) to 0.758 (T-58) (Trial 2) with serum 6. The greatest reactivity was observed with sera from two persons (2 and 3 from the same individual and serum 6) who became ill with symptoms of pulmonary disease and sought medical care. Both patients were subsequently diagnosed with blastomycosis by microscopic and culture methods. The study indicated that all of the lysate antigens, regardless of source, could be used to reliably diagnose blastomycosis.

Zipf distribution of U.S. firm sizes.

Analyses of firm sizes have historically used data that included limited samples of small firms, data typically described by lognormal distributions. Using data on the entire population of tax-paying firms in the United States, I show here that the Zipf distribution characterizes firm sizes: the probability a firm is larger than size s is inversely proportional to s. These results hold for data from multiple years and for various definitions of firm size.

Prevention of central venous catheter-related infections and thrombotic events in immunocompromised children by the use of vancomycin/ciprofloxacin/heparin flush solution: A randomized, multicenter, double-blind trial.

PURPOSE: To determine whether an antibiotic flush solution containing vancomycin, heparin, and ciprofloxacin (VHC) can prevent the majority of line infections. PATIENTS AND METHODS: A prospective double-blind study was performed comparing VHC to vancomycin and heparin (VH) to heparin alone in 126 pediatric oncology patients. RESULTS: The 153 assessable lines resulted in 36,944 line days studied. There were 58 blood stream infections (43 gram-positive, 14 gram-negative, and one fungal). Forty were defined as line infections (31 heparin, three VH, six VHC). The time to develop a line infection was significantly increased using either antibiotic flush (VH, P =.011; VHC, P =.036). The rate of total line infections (VH, P =.004; VHC, P =.005), gram-positive line infections (VH, P =. 028; VHC, P =.022), and gram-negative line infections (VH, P =.006; VHC, P =.003) was significantly reduced by either VH or VHC. Sixty-two (41%) of the lines developed 119 occlusion episodes (heparin, 3.99 per 1,000 line days; VHC, 1.75 per 1,000 line days; P =.0005). Neither antibiotic could be detected after flushing, and no adverse events were detected, including increased incidence of vancomycin-resistant Enterococcus colonization or disease. CONCLUSION: The use of either VH or VHC flush solution significantly decreased the complications associated with the use of tunneled central venous lines in immunocompromised children and would save significant health care resources.

Sensilla of the antennae and maxillary palps of Culicoides hollensis and C. melleus (Diptera: Ceratopogonidae).

The types and arrangement of the sensilla on the female antennae and maxillary palps of both sexes of 2 estuarine species of biting midges, Culicoides hollensis (Melander & Brues) and C. melleus (Coquillett), were studied by scanning electron microscopy. Five sensillum types are found on the antennae of both species. Both species have sharp-tipped sensilla trichodea and sensilla basiconica only on subsegments 9-13 and blunt-tipped sensilla trichodea on all subsegments. Sensilla coeloconica occur on subsegment 1 of both species and various other subsegments depending on the species. Sensilla chaetica are found on all subsegments of C. melleus, but only on subsegments 1-8 and 13 on C. hollensis. Both sexes of C. hollensis have either 1 or 2 pits on the 3rd segment of the maxillary palps, which contain 8-15 bulb-shaped sensilla in females compared with 5-6 in males. No pit is found on the maxillary palps of either sex of C. melleus, but rather the bulb-shaped sensilla are distributed individually on this segment, ranging from 13 to 29 on the female and 6-10 on the male palps. These data are compared with data obtained from previously published light and electron microscopical studies of biting midge sensory structures.

Hepatoblastoma metastatic to brain: prolonged survival after multiple surgical resections of a solitary brain lesion.

PURPOSE: Pulmonary metastases of hepatoblastoma confined to the lung have been cured using therapy that included radical surgical resection. We report the case of a child with a hepatoblastoma metastatic to brain that was successfully treated with multiple surgical resections, irradiation, and chemotherapy. The case demonstrates that such an approach, employing aggressive surgery, can produce durable remission of an extrapulmonary metastasis with hepatoblastoma. PATIENTS AND METHODS: A 17-month-old girl presented with a hepatoblastoma that remained unresectable after chemotherapy and irradiation and underwent orthotopic liver transplantation 14 months after diagnosis. After twice undergoing surgical resections of pulmonary metastases 22 and 31 months from diagnosis, 1 month later (32 months from diagnosis), she developed a solitary metastatic right brain lesion that later recurred twice in the same location, 5 and 6 years from initial diagnosis. Each time she underwent surgical resection of the brain lesion and received local irradiation after the first two resections and chemotherapy after the third. At the last surgery, resection was continued until histologically negative tumor margins were obtained. RESULTS: The child is currently without evidence of disease or neurological deficit 10.5 years from initial diagnosis. CONCLUSION: The durable remission achieved after multiple resections of the recurrent solitary cerebral metastasis in this child demonstrates that an aggressive surgical approach to extrapulmonary metastases in such a setting can contribute to prolonged survival, just as has been shown with isolated metastatic pulmonary disease.

Temperature-dependent development and survival of the lesser mealworm, Alphitobius diaperinus.

Development, growth and survival of the lesser mealworm, Alphitobius diaperinus (Panzer), were determined at six constant temperatures. No egg hatch or larval development occurred at 17 degrees C. At temperatures of 20, 25, 30, 35 and 38 degrees C the median development times (days), respectively, were for eggs (13.4, 6.0, 4.4, 2.6 and 2.6), larvae (133.0, 46.0, 26.2, 22.4 and 23.9), pupae (17.0, 8.0, 5.5, 4.0 and 4.1), and from oviposition to adult emergence (164.4, 60.2, 37.9, 29.0 and 30.8). The Sharpe & DeMichele (1977) model was used to describe the temperature-dependent development. The mean egg survival (hatching) ranged from 61% to 86%, with lowest hatch at 20 degrees C. Survival of the larvae and pupae ranged from 32% to 73% and from 85% to 95%, respectively, with lowest survival at 20 degrees C. Pupae had significantly lower weights at 35 degrees C and adults at 38 degrees C than at the other temperatures. Female pupae (20 mg) and female adults (16 mg) were significantly heavier than male pupae (17 mg) and male adults (13 mg). Adults (0.5-9 months old) laid 4-7 eggs per female per day at 25 degrees C.

Feeding behavior and growth of broiler chicks fed larvae of the darkling beetle, Alphitobius diaperinus.

Experiments were conducted to determine the effects of feeding larvae of the darkling beetle (lesser mealworm), Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) to broiler chicks on chick growth. Chicks readily fed on the larvae and exhibited reduced growth in the absence of other feed. Chicks 3 to 8 d old restricted to a diet of only larvae consumed 1,552 +/- 172 (mean +/- SD) larvae per chick per day and their body weights were significantly less (mean = 84 g) at the end of the 6 d than for chicks on starter feed during the same time. After return to starter feed for 8 d after feeding on larvae for 6 d, the chicks did not compensate for the reduced weight and their body weights were significantly less (mean = 170 g) than for chicks on starter feed for the 14 d. Chicks from age 2 through 9 d were given a choice between broiler starter feed and darkling beetle larvae. The numbers (mean +/- SD) of larvae consumed per chick per day were: 389 +/- 18, 631 +/- 14, 496 +/- 20, and 287 +/- 33, for Days 2 to 3, 4 to 5, 6 to 7, and 8 to 9, respectively. The body weight of chicks feeding on starter feed and larvae was significantly greater than the weight of chicks consuming feed only. In the presence of larvae, the mean feed consumption per chick was less than for chicks provided with only starter feed. The beetle larvae were 68% crude protein and 21% fat (DM basis) and had higher amounts of 18 amino acids than the starter feed.

Pediatric midbrain tumors: a benign subgroup of brainstem gliomas.

The presentation, radiographic findings and course of 17 children with MRI-documented intrinsic midbrain lesions are reviewed. The anatomic centers of all the lesions were tectal, peritectal, or tegmental. Lesions centered at the pineal gland were excluded. Signs of increased intracranial pressure from hydrocephalus requiring shunt placement were present in 14 patients. Histopathological diagnosis was confirmed in three tumors; these were low grade astrocytomas and all received focal irradiation, as did one unbiopsied tumor. The remaining 13 patients with no histopathological diagnosis received no therapy other than shunt placement in 11. All but one of the lesions have remained clinically and radiographically stable, with a 4-year progression-free and total survival of 94 and 100%, respectively. We conclude that mass lesions originating in the upper midbrain are a subset of intrinsic brainstem tumors with a relatively benign course, usually presenting with hydrocephalus after infancy. They may remain stable for considerable periods and may require no further therapy after treatment of hydrocephalus. Surgical biopsy and/or resection can usually be reserved for progressive or atypical lesions which may also require further adjuvant therapy.

Feeding behavior and growth of turkey poults fed larvae of the darkling beetle, Alphitobius diaperinus.

Experiments were conducted to determine the effects of feeding larvae of the darkling beetle (lesser mealworm), Alphitobius diaperinus (Panzer) [Coleoptera:Tenebrionidae], to turkey poults on poult growth and of beak trimming on poult feeding on the larvae. Young turkey poults readily fed on the larvae and exhibited reduced growth in the absence of other feed. Poults 3 to 5 d old restricted to a diet of only larvae consumed 259 +/- 99 (+/- SD) larvae per poult per day and their body weights were significantly lower (mean = 30 g) at the end of the 3 d than for poults on starter feed during the same time. After return to starter feed for 16 d after feeding on larvae for 3 d, the poults did not compensate for the weight loss although weight gains were normal. Poults from 2 through 10 d of age were given a choice between starter turkey feed and darkling beetle larvae. The numbers of larvae consumed per poult per day were: 174 +/- 8 for Days 2 to 4, 221 +/- 3 for Days 5 to 7, and 189 +/- 80 for Days 8 to 10. There was no significant difference between the body weight of poults feeding on larvae and starter feed compared with that of poults consuming feed only. In the presence of larvae, the mean feed consumption per poult was lower than for poults provided with only starter feed. The beetle larvae were 68% crude protein and 21% fat (DM basis) and had higher amounts of 18 amino acids than the starter feed. Poults that were beak trimmed consumed only about one-third as many larvae as poults with intact beaks. Poults (1 to 3 d old) with intact beaks consumed 169 +/- 20 larvae per poult per day; poults with trimmed beaks consumed 58 +/- 23 larvae per poult per day.

Comparisons of sampling methods and seasonal abundance of Drosophila repleta in caged-layer poultry houses.

Four sampling methods were compared to determine their practicality and suitability for detecting population fluctuations of adult Drosophila repleta, a pest in caged-layer poultry houses. Five caged-layer poultry houses with gutter-flush manure removal systems in Franklin County, North Carolina, U.S.A., were sampled once every 2 weeks over 15 months, from June 1991 to August 1992. The flies were most abundant during the spring and early summer. Visual counts of adult flies resting on the feed troughs in front of cages in the aisles and counts of flies caught on a sticky ribbon lowered into the gutter used for manure removal by flushing were more satisfactory sampling methods than using counts of flies caught on sticky ribbons carried along the aisles or aspirator collections from the gutters. For the visual count method, the effects of location in the house, within each aisle, and feed trough height were determined; two counts on feed troughs in each of two inside rows of cages were sufficient to measure population changes. For routine monitoring of D. repleta populations, visual counts of flies resting on the feed troughs in the front area of two aisles and catching flies on sticky ribbons inserted into the rear gutter area are recommended.

Low level CD20 expression on T cell malignancies.

Although initially thought to be a B lineage restricted antigen, low "density" or antibody binding capacity (ABC) CD20 has recently been detected on subset(s) of normal T lymphocytes (Hultin et al.: Cytometry 14:196-204, 1993). We report low ABC CD20 expression in three (two children, one adult) cases of T-acute lymphoblastic leukemia (T-ALL). CD20 and other pertinent antigens were detected using a direct dual color method with a Becton Dickinson FACScan flow cytometer and Simulset software. Only one cell population based on light scatter was noted in each case that immunophenotypically represented almost a pure population of malignant cells expressing T lymphocyte antigens (for example, CD7 98%, 92%, and 100%, respectively). A total of 95%, 87%, and 79% of the cells from the three cases expressed CD20 with an unusual low ABC compared to the customary "bright" CD20 expression on normal B lymphocytes. Other B lymphocyte associated antigens, such as CD19, CD22, Dr, and immunoglobulin light chains, were negative. Eleven other T lymphocytic malignancies from 1991 to 1993 were CD20 negative, including three other case of T-ALL (one adult and two children). One unusual case of intestinal small lymphocytic non-Hodgkin's lymphoma with a natural killer/T lymphocytic immunophenotype not described in this report appeared to be CD20"dim"+. Low ABC CD20 expression by T lymphocytic malignancies may provide a more unique immunophenotypic "fingerprint" to help support the diagnosis of T cell neoplasia vs. normal/reactive T cells (for example, low ABC CD20 cells represent only 2.4 +/- 1.5% of normal peripheral blood lymphocytes). This characteristic might also facilitate monitoring patients for residual or recurrent disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Brief unconscious sedation for painful pediatric oncology procedures. Intravenous methohexital with appropriate monitoring is safe and effective.

PURPOSE: We report here our experience in using intravenous methohexital (MHX), an ultrashort-acting barbiturate, for brief unconscious sedation of pediatric oncology outpatients undergoing painful, invasive procedures. METHODS: Following published monitoring guidelines for deep pediatric sedation, 1.0 mg/kg MHX was administered immediately before the procedure, 1% xylocaine was given locally, and MHX was additionally titrated to maintain minimal response to pain during the procedure. Clinical data reported here were gathered retrospectively from permanent medical records. RESULTS: Data reported here represent 132 evaluable consecutive procedures in 33 patients ranging in age from 1.6 to 20.5 years. Patients underwent an average of 4 +/- 3 procedures and received a mean total MHX dose per procedure of 5.8 +/- 2.1 mg/kg. The mean length of time from start of sedation to full arousability was 30 +/- 12 min. Twenty-three (17.4%) procedures were associated with clinically insignificant decreases in diastolic blood pressure or heart rate below resting normal ranges for age. Eight (6.1%) procedures in six patients were associated with minor complications requiring no intervention, such as transient behavioral changes, transient myoclonus, and minimal stridor. Five procedures (3.8%) in five patients required simple suctioning to manage secretions. Only two procedures (1.5%) in two patients required brief bag-mask ventilation plus suctioning for suspected laryngospasm. None required intubation. No differences in clinical features or MHX doses were noted for patients with, as compared to those without, complications. All procedures were completed with a satisfactory level of sedation. CONCLUSIONS: Our experience indicates that MHX, with appropriate monitoring as described here, is a safe and effective agent for use in pediatric oncology outpatient sedation programs.

Susceptibility of the bedbug, Cimex lectularius, to selected insecticides and various treated surfaces.

Adult bedbugs, Cimex lectularius, were exposed for 24 h (25 degrees C) to filter paper treated with various dilutions of the technical grade of nine insecticides dissolved in acetone to determine the concentration-response relationships. The order of toxicity, from most to least based on the LC50's was: dichlorvos, pirimiphos methyl, lambda-cyhalothrin, bendiocarb, permethrin, malathion, carbaryl, tetrachlorvinphos, and fenvalerate. The residual toxicities of commercial formulations of six of the chemicals diluted with water and applied to wood, cardboard, cloth and galvanized metal, were determined by exposing adult bedbugs at 3, 7 and 12 weeks after treatment. The formulation of bendiocarb (FICAM 76% W) had little residual activity on all surfaces at 12 weeks after treatment. The formulation of carbaryl (SEVIN 21.5% L) was toxic to bedbugs on all surfaces at 12 weeks after treatment, but required high concentrations on wood, cardboard, and cloth. The formulation of pirimiphos methyl (ACTELLIC 57% EC) had no residual activity on any of the surfaces at 12 weeks after treatment. The formulation of tetrachlorovinphos (RABON 50% W) had residual activity for 12 weeks on all surfaces except metal. The formulation of permethrin (ATROBAN 11% EC) had residual activity on only metal and wood while the formulation of lambda-cyhalothrin (KARATE 13.1% EC) had residual activity 12 weeks on all surfaces.

Susceptibilities of northern fowl mite, Ornithonyssus sylviarum (Acarina: Macronyssidae), and chicken mite, Dermanyssus gallinae (Acarina: Dermanyssidae), to selected acaricides.

The relative toxicities of ten acaricides to northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the chicken mite, Dermanyssus gallinae (De Geer), were determined simultaneously by holding the mites inside disposable glass Pasteur pipettes previously immersed in acetone solutions of various concentrations (w/v) of technical grade acaricides. The LC90s (parts per million) of the acaricides after 24 h exposure for the northern fowl mite and the chicken mite, respectively, were: bendiocarb (13.1, 0.18), tetrachlorvinphos (14.5, 4.07), carbaryl (15.0, 0.83), pirimiphos methyl (18.3, 2.03), permethrin (23.1, 8.46), lambda cyhalothrin (80.7, 11.4), dichlorvos (252.8, 3.75), malathion (238.4, 6.59), amitraz (6741, 9430) and fenvalerate (greater than 10,000, 60.2). After 48 h exposure there were only slight increases in mortalities of both species except for increased mortalities for the northern fowl mite with lambda cyhalothrin, amitraz and fenvalerate, and for the chicken mite with amitraz.