Repellency to ticks (Acari: Ixodidae) of extracts of Nigella sativa (Ranunculaceae) and the anti-inflammatory DogsBestFriend™.

Motivated by observations that the canine anti-inflammatory cream DogsBestFriend™ (DBF) appeared to deter flies, mosquitoes, and ticks from treated animals, repellent efficacy bioassays using four species of ticks were conducted with three extracts of Nigella sativa L. (Ranunculaceae), a constituent of DBF. The DBF cream was tested against nymphs of lone star tick, Amblyomma americanum (L.). In vertical filter paper assays, the three extracts applied at 0.413 mg extract/cm(2) filter paper repelled 96.7-100 % of brown dog tick, Rhipicephalus sanguineus (Latreille) nymphs, whereas, at the same rate, only one extract repelled >90 % A. americanum nymphs. Adult (mixed sexes) American dog ticks, Dermacentor variabilis (Say), required a higher concentration to be repelled effectively; two extracts, applied at 0.827 mg extract/cm(2) filter paper, repelled ≥90 % of the D. variabilis. In contrast, all extracts applied at much lower concentration (0.206 mg extract/cm(2) filter paper) repelled 100 % adult blacklegged ticks, Ixodes scapularis Say (only females tested). Of the two more repellent extracts, one lost most of its activity against A. americanum nymphs in <4 h when applied at 0.827 mg extract/cm(2) filter paper, whereas the other repelled 66.7 % of the nymphs at 192 h after application. At 0.206 mg extract/cm(2) filter paper, one extract was as repellent as deet against A. americanum nymphs. In a vertical bioassay in which nylon organdy was substituted for filter paper, DBF, at the rates of 1.67 and 0.835 mg cream/cm(2), repelled 76.7 and 30.0 % A. americanum nymphs, respectively. These findings indicate that when applied appropriately DBF should afford some protection to canines against tick bites.

Solvent, drying time, and substrate affect the responses of lone star ticks (Acari: Ixodidae) to the repellents deet and picaridin.

Behavioral bioassays remain a standard tool in the discovery, development, and registration of arthropod repellents. Tick repellent bioassays are generally uncomplicated, but their results can be affected by basic variables (e.g., dimensions of testing materials, substrate, timing, temperature) of the assay. Using lone star tick, Amblyomma americanum (L.), nymphs in climbing bioassays, we tested for the effects of substrate, solvent, and drying time on tick responses. In dose-response tests, the widely used repellents N,N-diethyl-3-methyl benzamide (deet) and 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (picaridin) were applied to filter paper strips and challenged by ticks at 10, 20, 30, 40, and 120 min after application. At 10-min drying time, repellency at the intermediate concentration 500 nmol repellent/cm2 filter paper was significantly lower for ethanol solutions of deet and picaridin (0 and 10% ticks repelled, respectively) than for solutions of deet and picaridin in acetone (96.7 and 76.7% ticks repelled, respectively). Repellency was greatest for both the acetone and ethanol solutions of deet and picaridin when challenged 120 min after application, and at shorter drying times at the highest concentration tested (2,000 nmol compound/ cm2). The repellency of picaridin relative to deet differed at some combinations of solvent and drying time but not others. In dose-response tests using different paper substrates and a drying time of 10 min, both ethanol and acetone solutions of deet differed in repellency, depending on both the paper substrate and the solvent. However, there were no differences in repellency between ethanol and acetone solutions of deet applied to nylon organdy in an in vitro and in an in vivo (fingertip) bioassay. When deet in solution with various proportions of ethanol:water was applied at 2,000 nmol deet/cm2 filter paper, the proportion of ticks repelled decreased as the proportion of water in the test solutions increased. Somewhat similar results were seen for solutions of deet in an acetone solvent. Water absorbed from the atmosphere may affect the efficacy of repellents in solution with anhydrous ethanol. Overall, results obtained from bioassays that differ in seemingly minor ways can be surprisingly different, diminishing the value of comparing studies that used similar, but not identical, methods. Nylon organdy or another similar thin cloth may be preferable to filter papers and copier paper for minimizing solvent-related differences. When a paper substrate is used, acetone may be the more suitable solvent if the solubility of the test compound and other factors allow.

Formulations of deet, picaridin, and IR3535 applied to skin repel nymphs of the lone star tick (Acari: Ixodidae) for 12 hours.

The efficacies of a 20% 1-methyl-propyl-2- (hydroxyethyl)-1-piperidinecarboxylate (picaridin) spray, 20% 3-(N-acetyl-N-butyl)aminopropionic acid ethyl ester (IR3535) spray, 20% picaridin lotion, 10% IR3535 lotion, and 33% N,N-diethyl-3-methylbenzamide (deet) cream in repelling nymphal lone star ticks, Amblyomma americanum (L.), were determined at 2-h intervals over 12 h using human subjects. A repellent formulation was applied in a 5-cm-wide band encircling a volunteer's lower leg. For each challenge, 70 host-seeking nymphs were released on each volunteer's ankle, and tick locations were recorded 10 min after the ticks were released. Ticks that crawled entirely across the repellent band were considered not repelled. For all formulations and time points, significantly fewer (all P < 0.0001) A. americanum nymphs crossed the treatment bands on the volunteers' ankles than crossed the corresponding area on the untreated control legs. Formulations containing > or = 20% active ingredient were highly effective, with <10% of the ticks crossing through the treatment bands for any challenge during the 12 h. At least 40% of ticks exposed to any formulation for any challenge fell or crawled off the volunteers. There was no difference in effectiveness between the 20% spray and 20% lotion formulations of picaridin. The 10% IR3535 lotion was significantly less effective than the formulations with higher concentrations of repellent. In the formulations tested, deet, picaridin, and IR3535 provided lasting protection against A. americanum.

Elemol and amyris oil repel the ticks Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) in laboratory bioassays.

The essential oil from Amyris balsamifera (Rutaceae) and elemol, a principal constituent of the essential oil of Osage orange, Maclura pomifera (Moraceae) were evaluated in in vitro and in vivo laboratory bioassays for repellent activity against host-seeking nymphs of the blacklegged tick, Ixodes scapularis, and the lone star tick, Amblyomma americanum. Both bioassays took advantage of the tendency of these host-seeking ticks to climb slender vertical surfaces. In one bioassay, the central portion of a vertical strip of filter paper was treated with test solution and ticks placed or allowed to crawl onto the untreated lower portion. In the other bioassay, a strip of organdy cloth treated with test solution was doubly wrapped (treatment on outer layer) around the middle phalanx of a forefinger and ticks released on the fingertip. Both amyris oil and elemol were repellent to both species of ticks. Elemol did not differ significantly in effectiveness against A. americanum from the widely used repellent deet. At 2 and 4 h after application to filter paper, 827 microg amyris oil/cm(2) paper repelled 80 and 55%, respectively, of A. americanum nymphs. Ixodes scapularis was repelled by lower concentrations of amyris oil and elemol than A. americanum.

Twelve-hour duration testing of cream formulations of three repellents against Amblyomma americanum.

The repellent efficacies of the U.S. military repellent 33% N,N-diethyl-3-methylbenzamide (deet), 10% and 20% (1S, 2'S) 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) and 10% and 20% 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (Bayrepel) cream formulations on human volunteers against the lone star tick Amblyomma americanum (L.) were evaluated in a simulated forest floor environment over a 12-h testing period. At 2-h intervals, volunteers, with repellent applied in a 5-cm-wide band around each ankle, stood for 5 min in plastic tubs containing leaf litter and 100 host-seeking A. americanum nymphs. Ticks were allowed to remain on a volunteer's feet and ankles for an additional 5 min after the volunteer exited the tub. All repellent formulations provided high levels of protection for the entire 12 h. No ticks crossed 5-cm-wide bands of 20% SS220 and Bayrepel during any challenge, and thus 100% protection was afforded throughout the test. These formulations showed a long-lasting efficacy hitherto unknown in tick repellents intended for use on human skin.

Reduced interference by gray squirrels with 4-poster deer treatment bait stations by using timed-release bait.

When white-tailed deer, Odocoileus virginianus, feed on corn bait dispensed by 4-poster tick control devices, they rub against paint rollers impregnated with acaricide. Gray squirrels, Sciurus carolinensis, also feed on the corn bait in the feeding troughs of 4-posters, but in doing so, leave abundant corn fragments and meal that impede the flow of uneaten corn into the troughs. Large accumulations of fragments and meal adversely affect the operation of 4-posters and their use by deer. A battery-operated closure mechanism controlled by a photo sensor was developed to block the flow of corn into the troughs during the day when squirrels are active and deer infrequently visit 4-posters. The effectiveness of the diurnal corn restriction (DCR) concept and restriction mechanism was tested in a field trial at a tick-infested site in Maryland. DCR effectively eliminated accumulation of whole corn, partially eaten corn and corn meal in corn troughs associated with squirrel feeding. At the same time, deer usage of 4-posters was not diminished.

Anointing chemicals and ectoparasites: effects of benzoquinones from millipedes on the lone star tick, Amblyomma americanum.

Many mammals and birds roll on or rub themselves with millipedes that discharge benzoquinones. Chemicals transferred from millipedes onto the integument of anointing animals are thought to deter ectoparasites. We tested the lone star tick, Amblyomma americanum (L.), for responses to three widespread components of millipede defensive secretions, 1,4-benzoquinone; 2-methyl-1,4-benzoquinone (toluquinone); and 2-methoxy-3-methyl-1,4-benzoquinone (MMB). In toxicity tests, ticks were confined for 1 hr in filter-paper packets treated with serial dilutions of each of the benzoquinones or the commercial acaricide permethrin. Ticks were least affected by toluquinone, and most affected by permethrin. Of the benzoquinones, only MMB showed repellent activity. Behavioral assays were more sensitive than mortality for measuring the effects of the benzoquinones. Latencies for ticks to right themselves and to climb were greater with all compounds, even at the lowest concentrations, than with controls. Ticks exposed to low concentrations of benzoquinones appeared to recover over time, whereas those exposed to high concentrations exhibited behavioral abnormalities 1-3 mo later. Our results indicate that benzoquinones appropriated via anointing may reduce the tick loads of free-ranging animals, although key questions remain on the amounts of these compounds available to and effectively appropriated by anointing animals.

Repellency of deet and SS220 applied to skin involves olfactory sensing by two species of ticks.

Responses of host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say and lone star tick, Amblyomma americanum (Linnaeus) (Acari: Ixodidae) to the repellents N,N-diethyl-3-methylbenzamide (deet) and (1S, 2'S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) were studied using fingertip laboratory bioassays. Ethanol solutions of both compounds applied to the skin strongly repelled both species of ticks at 0.8 and 1.6 micromole of compound/cm2 skin. The ticks were also repelled when two layers of organdie cloth covered the portion of a finger treated with either deet or SS220. Gas chromatographic analyses of the outer layer of cloth that had covered skin treated with 1.6 micromole compound/cm2 skin revealed only 0.1 nmole SS220/cm2 cloth and 2.8 nmole deet/cm2 cloth. However, in bioassays in which a single layer of cloth was treated with a dose of deet or SS220 equivalent to the amount found in the outer layer of cloth, ticks were not repelled. Results unequivocally demonstrated that these ticks responded to the repellents in the vapour phase when repellent treated skin was covered with cloth to obviate tactile contact with them, and made it clear that the ticks detect the repellents by olfactory sensing. Heretofore, the mode of action of deet and SS220 was unclear.

Ectopic fat storage in heart, blood vessels and kidneys in the pathogenesis of cardiovascular diseases.

In humans and most animal models, the development of obesity leads not only to increased fat depots in classical adipose tissue locations but also to significant lipid deposits within and around other tissues and organs, a phenomenon known as ectopic fat storage. The purpose of this review is to explore the possible locations of ectopic fat in key target-organs of cardiovascular control (heart, blood vessels and kidneys) and to propose how ectopic fat storage can play a role in the pathogenesis of cardiovascular diseases associated with obesity. In animals fed a high-fat diet, cardiac fat depots within and around the heart impair both systolic and diastolic functions, and may in the long-term promote heart failure. Accumulation of fat around blood vessels (perivascular fat) may affect vascular function in a paracrine manner, as perivascular fat cells secrete vascular relaxing factors, proatherogenic cytokines and smooth muscle cell growth factors. Furthermore, high amounts of perivascular fat could mechanically contribute to the increased vascular stiffness seen in obesity. Finally, accumulation of fat in the renal sinus may limit the outflow of blood and lymph from the kidney, which would alter intrarenal physical forces and promote sodium reabsorption and arterial hypertension. Taken together, ectopic fat storage in key target-organs of cardiovascular control may impair their functions, contributing to the increased prevalence of cardiovascular diseases in obese subjects.

Comparative activity of deet and AI3-37220 repellents against the ticks Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) in laboratory bioassays.

The repellents N,N-diethyl-3-methylbenzamide (deet) and racemic 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were evaluated using two different laboratory bioassays to determine their relative effectiveness against host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and the lone star tick, Amblyomma americanum (L.). In a petri dish bioassay, ticks were released within a ring of repellent on a horizontal filter paper disk. In the second bioassay, ticks were allowed to climb a vertical strip of filter paper whose central portion was treated with a repellent. Deet and AI3-37220 were more effective against I. scapularis than A. americanum nymphs. In the petri dish bioassay, none of the concentrations of deet or AI3-37220 tested confined A. americanum within the treated ring. However, in the vertical bioassay, both species exhibited avoidance of the repellents, and I. scapularis was repelled by much lower concentrations than A. americanum. I. scapularis were repelled by lower concentrations in the vertical bioassay than in the petri dish bioassay. Deet was slightly more effective against I. scapularis than AI3-37220 in both bioassays, but AI3-37220 was significantly more effective than deet against A. americanum in the vertical bioassay.

Hydralazine as antihypertensive therapy in obesity-related hypertension.

OBJECTIVE: The objectives were two-fold: (1) determine whether the use of hydralazine as antihypertensive therapy during obesity development exacerbated obesity-related cardioacceleration and hormonal abnormalities; (2) determine whether the absence of hypertension in obesity attenuated obesity-related abnormalities in hemodynamics, cardiac hypertrophy, and hormonal profile. DESIGN: Female New Zealand White rabbits were divided into lean control (n=12), lean hydralazine-treated (n=9), obese control (n=11), and obese hydralazine-treated (n=8) groups. Pretreatment mean blood pressure (BP) and heart rate (HR) were determined using telemetry. Pretreatment BP was maintained during 12 weeks of obesity development using hydralazine. MEASUREMENTS: Chronically measured BP and HR; plasma/blood volume; wet and dry ventricular weights; body fat/water; and hormonal profile (plasma renin activity, aldosterone, cortisol, atrial natriuretic peptide, adrenaline, and noradrenaline). RESULTS: Hydralazine treatment in obese animals attenuated obesity-related renin-angiotensin system (RAS) activation. In contrast, RAS was activated in lean hydralazine, as indicated by increased plasma aldosterone. The absence of hypertension in obese hydralazine did not result in attenuation of cardioacceleration, cardiac hypertrophy, or intravascular volumes. CONCLUSIONS: Hydralazine treatment in obese rabbits did not exacerbate obesity-related cardiovascular and hormonal alterations. Cardioacceleration and cardiac hypertrophy persisted in obese hydralazine despite BP control, suggesting hypertension-independent effects of obesity on these variables. Hydralazine's effects on RAS activation differed in lean and obese rabbits, suggesting that the systemic effects of hydralazine as a control therapy in evaluation of antihypertensive medications may differ depending on the underlying pathology.

A cautionary note: survival of nymphs of two species of ticks (Acari: Ixodidae) among clothes laundered in an automatic washer.

Host-seeking ticks often remain on clothing of persons returning home from work or recreation in tick habitats, and can pose at least a temporary risk to people and pets in these homes. Laundering clothing has been one of the recommendations to reduce tick exposure. Host-seeking lone star tick, Amblyomma americanum (L.), and blacklegged tick, Ixodes scapularis Say, nymphs confined in polyester mesh packets, were included with laundry in cold, warm, and hot wash cycles of an automatic clothes washer. Ticks were also placed with washed clothing and subjected to drying in an automatic clothes dryer set on high heat and on air only (unheated). Most nymphs (> or = 90%) of both species survived the cold and warm washes, and 95% of A. americanum nymphs survived the hot wash. At the time of their removal from the washer, I. scapularis nymphs were clearly affected by the hot wash, but 65% were considered alive 20-24 h later. Large percentages of nymphs of both species survived hot washes in which two other detergents (a powder containing a nonchlorine bleach and a liquid) were used. All ticks were killed by the 1 h cycle at high heat in the clothes dryer, but with unheated air some nymphs of both species survived the 1 h cycle in the dryer. Given the laundering recommendations of clothing manufacturers and variation in the use automatic clothes washers, laundry washed in automatic washers should not be considered free of living ticks.

Winter activity of Ixodes scapularis (Acari: Ixodidae) and the operation of deer-targeted tick control devices in Maryland.

Host-seeking activity of adult blacklegged ticks, Ixodes scapularis Say was monitored by flagging during winter months in Beltsville, MD. Ticks were active many days during January and February, the coldest months, with some captures made when there was 70% snow cover and temperatures as low as -2 degrees C. Substantial numbers (70-90 ticks/h of flagging) of adult I. scapularis were captured on favorable days in January and February. The cost to treat white-tailed deer, Odocoileus virginianus (Zimmermann), using '4-poster' deer self-treatment devices, was estimated on a per female tick basis. We estimated deer abundance and tick attachment rates using data from the literature, tick activity levels using weather data and drag counts of ticks, and costs to operate the devices from experience. We found that self-treatment devices need not be operated continuously from late December until the third week of February. On average, savings of half the operating costs would be realized by not operating the devices when tick activity was low.

beta-Adrenoceptor density and adenylyl cyclase activity in obese rabbit hearts.

OBJECTIVE: To determine whether decreased cardiac responsiveness to isoproterenol in obesity is associated with alterations in beta-receptors and/or adenylyl cyclase activity. ANIMALS AND DESIGN: After 12 weeks of control or ad libitum high-fat diets, left ventricular tissue from lean and obese female New Zealand white rabbits was assayed for beta-receptor binding density (11 lean, 11 obese) and isoproterenol-stimulated adenylyl cyclase activity (eight lean, 10 obese). MEASUREMENTS: Nonlinear least squares regression analysis was used to determine maximum density of beta-receptors and receptor affinity for (125)I-iodocyanopindolol. Four-parameter logistic regression was used to determine minimum, maximum, slope and EC(50) for isoproterenol-stimulated adenylyl cyclase activity. RESULTS: Obese rabbits had elevated resting blood pressure and heart rate, and higher ventricular weights. However, beta-adrenoceptor density and affinity were not significantly different in lean and obese rabbits. Basal and maximum isoproterenol-stimulated adenylyl cyclase activity did not differ between lean and obese rabbits. In addition, maximal stimulation in response to sodium flouride did not differ between lean and obese. EC(50) for isoproterenol-stimulated adenylyl cyclase activity did not differ between lean and obese rabbits. CONCLUSION: Obesity-related decreases in responsiveness of the isolated heart to isoproterenol are not associated with alterations in beta-receptor density and affinity. In addition, adenylyl cyclase activity appeared unchanged in ventricular preparations from obese rabbits. Decreased responsiveness to isoproterenol in obesity may be due to defects downstream of adenylyl cyclase activation of cyclic AMP.

A survey for nymphs of host-seeking Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) on tree trunks in deciduous forests.

Trunks of 83 trees in a mixed deciduous forests in Maryland were sampled for the presence of nymphs of the blacklegged tick, Ixodes scapularis Say, and the lone star tick, Amblyomma americanum (L.). Although one or more nymphs of either I. scapularis or A. americanum was found in leaf litter and substrate < or = 1 m from the bases of 47% of the trees sampled, a total of 6 I. scapularis nymphs was found on the trunks of only five trees. No nymphs were found on the trunks of 12 dead trees. No A. americanium nymphs were found on any tree trunks. The trunks were sampled to 2.5 m above the soil, but the nymphs were found < or = 1 m from the ground. More than 50% of I. scapularis nymphs found in the leaf litter < or = 1 m from bases of living trees were north of the trees sampled, whereas few I. scapularis were found west of trees. These findings suggest that the I. scapularis nymphs' presence on tree trunks is of little ecological consequence, unless nymphs were being removed from tree trunks by acquiring hosts at such a rapid rate that nymphal numbers on trunks could not accrue.

Accuracy and utility of 3-dimensional computed tomography in evaluating donors for adult living related liver transplants.

Three-dimensional (3D) computed tomography (CT) is an imaging technique that renders anatomic detail in 3D images from helical computed tomographic scans. The purpose of this study is to assess 3D CT in the preoperative evaluation of adult living related liver transplant donors. Nine patients underwent right-lobe liver resection for adult living related liver transplants between October 1999 and September 2000. All donors underwent triphasic helical CT of the liver with 3D computed tomographic reconstruction and conventional angiography. The 3D images were correlated with angiography and intraoperative findings. The origin of vessels, relative length of segments, and position of branches were considered for accuracy. The 3D computed tomographic images were compared with angiograms to determine whether angiography could be replaced by 3D CT. 3D CT identified all variations of the hepatic vein confluences and portal vein trifurcations and all hepatic arterial variants. At surgery, the 3D computed tomographic images of hepatic and portal veins were judged to be accurate and helpful in 8 of 9 cases, and images of the hepatic artery, accurate and helpful in 5 of 9 cases. The 3D computed tomographic images of hepatic and portal veins were better than or equivalent to angiograms in nearly all cases. The 3D computed tomographic images of the hepatic artery were better than or equivalent to angiography in 5 of 9 cases. By providing an accurate 3D map of the liver and its vasculature, 3D computed tomographic reconstructions of the hepatic vasculature are a useful adjunct for surgical planning in adult living related liver donors. 3D CT clearly delineates portal and hepatic veins as well as or better than the angiogram and can identify the hepatic artery and its branches well enough to consider replacing angiography, thus reducing cost, inconvenience, and risk to the donor.

Exploring the self-reported sexual problems and concerns of drug-dependent males and females in modified, therapeutic community treatment.

The importance of sexual trauma and sexual problems in the treatment of chemically dependent persons has long been recognized by clinicians working with this population. This study was undertaken to describe the degree of self-reported sexual problems and concerns for 163 males admitted into a Philadelphia- or New York City-based modified therapeutic community (TC) program and 100 females admitted to the same New York City program. Results indicated that the majority of men and women identified some sexual problems and concerns shortly after being admitted, with females in the New York City sample endorsing sexual problems more often than males in the Philadelphia or New York City samples. These findings are considered in view of the fact that these clients' sexual problems were usually not addressed on their Master Treatment Plans. The implications of addressing or not addressing these sexual problems are considered.

Different activities and footwear influence exposure to host-seeking nymphs of Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae).

The relative potential for a person accidentally acquiring host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and lone star tick, Amblyomma americanum (L.), while wearing either of two types of footwear, walking, crawling on hands and knees, and sitting on large fallen logs in deciduous woods, was evaluated. Although flag samples indicated substantial populations of I. scapularis nymphs and low to moderate numbers of A. americanum at the study sites, relatively few I. scapularis and fewer still A. americanum nymphs were acquired during 30-s and 5-min walks. Significantly fewer I. scapularis were picked up when boots were, worn with ankles taped (an anti-tick precaution) than when sneakers were worn with socks exposed during 5-min walks, but when thus attired, there was no significant difference between the number of nymphs acquired during 30-s walks. Nymphs of I. scapularis did not appear to accumulate incrementally on footwear or clothing during walks when boots were worn and ankles taped. Crawling for 30 s (approximately 3 m distance) yielded significantly more I. scapularis nymphs than walking for 30 s. During crawling, I. scapularis nymphs were picked up on 58% of the 30-s samples. Most ticks picked up during crawls were on pant legs. When a flannel flag cloth (0.5 by 0.5 m) was appressed to the upper surface of logs suitable to be sat upon by tired hikers, I. scapularis nymphs were found on 87% of the logs and in 36% of the samples. These data indicate that the potential for contact with host-seeking nymphs of I. scapularis occurring at these densities is greatly elevated by engaging in activities that involve contact with fallen logs and close contact of hands and knees with leaf litter.

Interdigital gland substances of white-tailed deer and the response of host-seeking ticks (Acari: Ixodidae).

Host-seeking male and female blacklegged ticks, Ixodes scapularis Say, exhibited an arrestant response when contacting substances from front and rear interdigital glands of male and female white-tailed deer, Odocoileus virginianus (Zimmermann). Female I. scapularis responded positively to substances from interdigital glands on the fore legs and hind legs of female deer, whereas male I. scapularis responded only to samples from the fore legs of does. These results showed that previously reported responses of I. scapularis to residues from interdigital glands of hind legs of deer were independent of tarsal gland substances, which may contaminate interdigital gland substances on hind legs. Nymphs of I. scapularis and female lone star ticks, Amblyomma americanum (L.), did not show an arrestant response to substances from hind legs of does, but male A. americanum did.

The altered structure of renal papillary outflow tracts in obesity.

Weight gain is associated with an expanded renal medullary interstitium in humans and in animal models of obesity. In this study, the consequence of obesity and this expanded matrix on renal papillary structure was examined in 15 obese rabbits fed a high fat diet for 8-12 weeks compared to 21 rabbits fed a standard diet. When examined under a dissecting microscope, the tips of the renal papillae from formalin-fixed, methylene blue-stained kidneys showed patent ducts of Bellini in 5 of 5 instances from 2 lean rabbits, but in only 2 out of 12 ducts from 3 obese rabbits. The ostia of the remaining ducts were significantly distended (205 +/- 42 microns versus 56 +/- 8 microns) and occupied by lightly staining granular material. When examined with scanning electron microscopy, all ducts were patent in lean rabbits (6 ducts in 4 rabbits, averaging 104 +/- 12 microns across), whereas only 6 of 11 ducts were patent in papillae from 4 obese rabbits. Renal medullary parenchymal tissue appeared at the openings of the remaining 5 ducts of Bellini in the 4 rabbits. Not only were these 5 ducts significantly distended by the interstitial material (with openings averaging 248 +/- 56 microns across), but the associated collecting ducts were dilated relative to control (100 +/- 15 microns versus 75 +/- 7 microns). Since the ducts of Bellini are the only renal openings that are not corsetted by a fibrous capsule, the authors speculate that the expanded medullary interstitium and increased renal sinus lipid partially obstruct renal outflow and elevate renal interstitial hydrostatic pressure in obesity, causing a prolapse of parenchymal contents, further obstructing urine outflow and leading to distention of the collecting ducts and ducts of Bellini.