Acaricide resistance in northern fowl mite (Ornithonyssus sylviarum) populations on caged layer operations in Southern California.

Southern California caged layer operations were visited over 3 yr. Northern fowl mites from 26 field populations were tested for acaricide resistance using a capillary pipette and glass dish bioassay. One was a susceptible field population with no pesticide exposure for over 30 yr (reference site for resistance ratio calculation). Technical and commercial formulations of malathion, carbaryl (Sevin), permethrin, and a commercial formulation of tetrachlorvinphos/dichlorvos (Ravap) were tested. Malathion did not have high activity for mites relative to other materials, but resistance to both technical and commercial formulations was low (< 5x). Resistance to other materials was moderate to extreme. Frequency of carbaryl resistance (> 10x) was higher with the commercial (88%) than the technical material (41%); 19% of the populations had resistance > 100x to commercial carbaryl. Frequency of Ravap resistance (> 10x) was 68%; 8% of populations had resistance > 100x. Frequency of permethrin resistance (> 10x) was 72% for the technical material and 88% for the commercial formulation. Extreme permethrin resistance (> 1,000x) was observed in 56 and 50% of mite populations assayed using the technical and commercial formulations, respectively. Among sites, resistance to permethrin was uncorrelated with resistance to other chemicals, suggesting a different resistance mechanism. Resistance to carbaryl and Ravap was highly correlated [r = 0.76 at the LC50 level (concentrations estimated to be lethal to 50% of the test population) and r = 0.99 at the LC95 level], suggesting a common resistance mechanism. Producers currently depend completely on pesticides to control mite infestations. Mite resistance to registered materials emphasizes the need for integrated control measures.

[Photodynamic therapy: extended indication]. / Photodynamische Therapie: erweiterte Indikationen.

OBJECTIVE: Evaluation of efficacy of photodynamic therapy (PDT) for classic choroidal neovascularization (CNV) beyond the common indication. METHODS: A group of 256 patients was treated with photodynamic therapy from January to December 2000. Ten of these patients had a predominantly classic CNV due to angioid streaks (5), parafoveal telangiectasia (2), or chorioretinitis (3). In two patients an idiopathic origin of the CNV was presumed. Another 21 patients showed a juxtafoveal classic membrane (12) or a recurrence after laser photocoagulation (9). Visual acuity was evaluated, also in correlation to age and CNV size. Continuous follow-up of CNV and leakage size was performed with fluorescein angiography. RESULTS: Overall 85% of the patients showed visual stabilization or improvement during an average observation period of 10.5 months. A correlation was found between age and visual improvement favoring younger patients; however, no correlation was found between visual improvement and CNV size. CNV and leakage size decreased moderately over the 9-month follow-up from 1.81/3.45 mm(2) to 1.61/2.60 mm(2). CONCLUSION: PDT shows efficacy for classic choroidal neovascularization beyond the common indication.

An automated feeding apparatus for in vitro maintenance of the human head louse, Pediculus capitis (Anoplura: Pediculidae).

An automated feeding apparatus was developed to maintain the human head louse (Pediculus capitis DeGeer) in vitro. With the use of valves and timers, banked human blood and saline from refrigerated reservoirs were pumped into and flushed out of the system every 7 d. During this rotational interval, bloodmeals were provided to head lice continuously and ad libitum through a stretched Nescofilm-silicone sandwich membrane. Compared with our previous in vitro human head louse-rearing apparatus, greater numbers of lice could be fed simultaneously with minimal human monitoring. Development of second to third instars and third instars to adults was significantly faster when lice were reared in vivo than on either of the in vitro rearing systems; there was no significant difference in the duration of the first instar. Although fecundity and hatch rates were significantly higher for female lice reared in vivo, similar trends have been observed for other membrane-fed arthropods. Body lice (Pediculus humanus L.) and bed bugs (Cimex lectularius [L.]) also completed most of their life cycle on this apparatus. Our automated mass-rearing system has broad applications for maintaining fluid-sucking ectoparasites and will facilitate various toxicological, behavioral, and disease-transmission investigations.

Failure of a permethrin treatment regime to protect cattle against bluetongue virus.

Holstein heifers in a confined feedlot setting on a southern California dairy were either sprayed individually along the ventral midline using 0.2% permethrin (250 ml/animal) (two pens) or were not treated (two pens). Treatments (n = 6 dates) were applied every 2 wk during the peak fall bluetongue virus transmission season (22 August-29 October). Animals seronegative for bluetongue virus antibodies at the initial bleeding on 15-18 September (n - 106 in the treatment pens and n = 117 in the control pens) were bled again for testing 2 mo later (12-13 November). Seroconversion rates were not significantly different: 56% for the treated animals and 48% for the controls (P > 0.2). The area has many essentially contiguous, confinement dairies with wastewater ponds that produce large numbers of Culicoides sonorensis Wirth & Jones, the primary bluetongue virus vector. Further, these dairies presumably provided a large reservoir of virus-infected cattle to infect vectors in the immediate area. Under these severe virus challenge conditions, permethrin applied at 2-wk intervals failed to reduce exposure to bluetongue virus.

The neuroprotective properties of gabapentin-lactam.

BACKGROUND: Gabapentin-lactam (GBP-L) is a derivative of the anti-convulsivant drug gabapentin. In vitro, GBP-L diminished the hypoxia-induced release of the neurotransmitter and excitotoxin glutamate. This effect could be reversed with glibenclamide, indicating that GBP-L acts as an opener of ATP-sensitive potassium channels. In vivo, GBP-L was neuroprotective in a rat model of acute retinal ischemia. In this study we investigated the time- and dose-effect relationship of this neuroprotection. METHODS: In each treatment group (n=9), retinal ischemia was induced in the left eye by pumping air into the anterior chamber to an intraocular pressure of 120 mmHg for 1 h. Two weeks later, neuronal damage in the ganglion cell layer was histologically quantified. Group 1 received vehicle only; group 2 received 75 mg/kg GBP-L i.p. at the beginning of ischemia; groups 3, 4, 5, 6, and 7 received the same dose at 1, 2, 3, 4, and 5 h after onset of reperfusion. Subgroups 5b and 5c received 50 and 25 mg/kg, respectively, 3 h after reperfusion. Each injection was repeated once after 6 h. RESULTS: The proportions of neurons that survived in groups 1 to 7 were 28%, 70%, 59%, 55%, 58%, 45%, and 37%, respectively. The proportions of neurons surviving in groups 5b and 5c were 49% and 39%, respectively. The difference in neuronal survival between group 1 and groups 2, 3, 4, 5, 5b, and 6 was statistically significant. CONCLUSION: GBP-L was neuroprotective in an animal model of acute retinal ischemia, even when given up to 4 h after reperfusion. GBP-L may prove useful in optic neuropathies such as glaucoma.

Feeding and survival of Culicoides sonorensis on cattle treated with permethrin or pirimiphos-methyl.

The persistence of permethrin (5% a.i.) and pirimiphos-methyl (27% a.i.), applied to the dorsum of calves in the field against Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae), was estimated using a hair-blood-feeding bioassay in the laboratory. Hair clippings were taken before treatment and 3, 7, 14, 21, 28, 42 and 56 days after treatment from the dorsum, side and belly of treated and control calves. Laboratory-reared insects were allowed to feed through thin hair layers and a parafilm membrane on sheep blood warmed using a water-jacketed feeder. Some intoxication after exposure to hair was noted up to 28 days after treatment with permethrin and up to 14 days after treatment with pirimiphos-methyl. Hair from the dorsum caused more intoxication for a longer period than hair from other body regions. Permethrin and pirimiphos-methyl applied to the back did not significantly reduce overall engorgement (body regions pooled) after treatment. Permethrin residues on hair remained far higher on the back than other body regions and were related to insect intoxication and reduction in engorgement in the laboratory. Residues on belly hair never exceeded 12p.p.m. and did not result in significantly reduced feeding at any time. Engorged insects that exhibited sublethal intoxication from feeding through permethrin-treated hair did recover and matured numbers of eggs comparable to controls. Field trials using treated and control calves and enclosure nets showed that dorsal applications of 5% permethrin were not effective in reducing engorgement, despite some intoxication. Vacuum samples from a calf showed that C. sonorensis fed primarily on the belly. A 0.2% permethrin application on the belly (250 ml) did result in > 80% reduction of C. sonorensis in the enclosure nets at 3 and 7 days after treatment, but activity had subsided by 10 days after treatment. The utility of insecticidal treatments for suppression of this vector is discussed.

[Measuring retinal circulation with the Heidelberg retinal flowmeter: reproducibility of data and no effect of metipranolol in normal probands]. / Messung der retinalen Durchblutung mit dem Heidelberg Retina Flowmeter: Reproduzierbarkeit der Daten und kein Einfluss von Metipranolol an Normalpersonen.

PURPOSE: We wanted to know whether topical Metipranolol has any effect on ocular blood flow. Before starting this investigation using the Heidelberg Retina Flowmeter, we studied the reproducibility of this device. METHOD: Retinal blood flow was determined in 15 healthy volunteers. Altogether, each volunteer was measured 20 times (4 different days with 5 pictures each). Coefficients of variation were calculated for both, the short term fluctuation and the long term fluctuation. After that, the effect of metipranolol was tested in 14 of the 15 volunteers mentioned above. This was done in a randomized, placebo controlled, double masked and crossover designed study. RESULTS: The mean coefficients of variation were 21% for the short term fluctuation and 13% for the long term fluctuation. There was a significant effect of learning, i.e. coefficients of variation decreased with increasing experience of the investigator (MVR). Blood flow values did not differ significantly between metipranolol and placebo. CONCLUSIONS: 1. The reproducibility of blood flow values measured with the Heidelberg Retina flowmeter are sufficient, at least if the device is used in clinical studies. When performing those studies, the learning curve of the investigator should be taken into account. 2. The topical application of metipranolol does not alter the retinal blood flow in healthy volunteers.

Field morphological variation and laboratory hybridization of Culicoides variipennis sonorensis and C. v. occidentalis (Diptera:Ceratopogonidae) in southern California.

Two field populations of Culicoides variipennis (Coquillett) from southern California, C. v. occidentalis Wirth & Jones from the Salton Sea and C. v. sonorensis Wirth & Jones from a dairy wastewater pond in the Chino Basin, were sampled monthly from February to July (6-7 mo). Morphometric analyses of slide-mounted adults reared from field-collected larvae and pupae indicated that females of the 2 forms were indistinguishable. Two of the standard characters, wing length and mandibular teeth, were correlated with seasonal temperature changes. Males of C. v. sonorensis were distinguishable by the presence of spicules on the aedeagus, which were entirely lacking in C. v. occidentalis. Two populations of C. v. occidentalis (Salton Sea and Bolsa Chica Marsh) and a laboratory strain of C. v. sonorensis hybridized successfully in the laboratory and were maintained for 6 generations. Differential hybrid viability (F1) was observed in reciprocal crosses. Males of C. v. occidentalis mated with females of C. v. sonorensis resulted in a lower egg hatch (7.4%) than did the reciprocal cross (75.6%). Hybrid males displayed spicules on the aedeagus (a character of C. v. sonorensis), but the number of spicules was sometimes reduced compared with parental C. v. sonorensis (AA strain). Spicules in a field population of C. v. sonorensis were similar in number to the laboratory C. v. sonorensis-C. v. occidentalis hybrids. Based on successful hybridization, the 2 forms should be considered closely related. The 2 forms are separated ecologically by the nature and distribution of their larval habitats.

Lachnellins A, B, C, D, and naphthalene-1,3,8-triol, biologically active compounds from a Lachnellula species (ascomycetes).

In the course of our search for new biologically active metabolites, lachnellin A (1), a metabolite with high cytotoxic and antimicrobial activities, the structurally related lachnellins B, C and D (3, 4, 7), and naphthalene-1,3,8-triol (8), an inhibitor of malate synthase (EC 4.1.3.2), were isolated from submerged cultures of the ascomycete Lachnellula sp. A 32-89. The antimicrobial, cytotoxic and phytotoxic activities of lachnellin A depended on its reactivity and could be abolished by the addition of cysteine. The enzyme inhibiting activity of (8) was due to reactive intermediates during melanization and was no longer observed in the presence of serum albumin. In addition, rac-scytalone (9), (+)-trans-3,4-dihydro-3,4,8-trihydroxy-1 (2H)-naphthalenone (10), 2,5-dihydroxytoluene (11), and (R)-(-)-5-methylmellein (12) were obtained from the same source and biologically characterized.

Darlucins A and B, new isocyanide antibiotics from Sphaerellopsis filum (Darluca filum).

Two new xanthocillin type antibiotics, darlucin A (1) and B (2), were isolated from fermentations of Sphaerellopsis filum (Darluca filum). Their structures were established by spectroscopic methods. The darlucins are the first known compounds with a 1,2-diisocyanoalkene moiety. Both compounds exhibited antibacterial, antifungal and weak cytotoxic activities.

Kuehneromycins A and B, two new biological active compounds from a Tasmanian Kuehneromyces sp. (Strophariaceae, Basidiomycetes).

In a search for new inhibitors of RNA-directed DNA-polymerases kuehneromycin A (1) was isolated from fermentations of a Tasmanian Kuehneromyces species. Its structure was elucidated by spectroscopic methods. Kuehneromycin A (1) is a non-competitive inhibitor of avian myeloblastosis virus (Ki 200 microM) and moloney murine leukemia virus (Ki 40 microM) reverse transcriptases. The second compound, kuehneromycin B (2) is a strong inhibitor of platelet aggregation stimulated with different inducers. In addition, both compounds exhibit cytotoxic and antimicrobial activities.

Temperature Effects on Survival and Development of Heleidomermis magnapapula in the Laboratory.

The mermithid Heleidomermis magnapapula Poinar and Mullens, a parasite of the biting midge Culicoides variipennis (Coquillett), was exposed to constant temperatures in the laboratory. Survival of the free-living stages and development times of eggs and the parasitic phase were inversely related to temperature. Average preparasite longevity was 70, 46, 42, and 22 hours at 15.6, 21.1, 26.7, and 32.2 C, respectively. Females survived significantly longer than males. Longevity in days (females/males) at different temperatures was 17.3/11.0 at 4.4 C, 9.0/8.2 at 15.6 C, 5.9/5,1 at 21.1 C, 5.2/4.7 at 26.7 C, and 4.4/3.6 at 32.2 C. Embryogenesis required 44 +/- 2 degree days above a thermal minimum of 10.1 C, while parasitic development in host larvae required 214 +/- 10 degree days above a thermal minimum of 8.9 C. Parasite responses to temperature were very closely related to temperature-dependent host development patterns.

Caloporoside, a new inhibitor of phospholipases C from Caloporus dichrous (Fr.) Ryv.

A new salicylic acid derivative, caloporoside, was isolated from fermentations of Caloporus dichrous. Its structure was elucidated by a combination of chemical and spectroscopic methods. Caloporoside exhibits weak antibacterial and antifungal activities and is a quite selective inhibitor of phospholipase C isolated from pig brain (Ki 12, 3 microM).

The mniopetals, new inhibitors of reverse transcriptases from a Mniopetalum species (basidiomycetes). II. Structure elucidation.

The structures of six new drimance sesquiterpenoids, mniopetals A-F, were elucidated by a combination of chemical and spectroscopic methods. The mniopetals are inhibitors of RNA-directed DNA-polymerases.

Hyphodontal, a new antifungal inhibitor of reverse transcriptases from Hyphodontia sp. (Corticiaceae, Basidiomycetes).

In a search for inhibitors of RNA-directed DNA polymerases a new isolactarane sesquiterpenoid, hyphodontal (1), was isolated from fermentations of a Canadian Hyphodontia species. Its structure was elucidated by spectroscopic methods. Hyphodontal strongly inhibits the growth of several yeasts and is a non-competitive inhibitor of avian myeloblastosis virus (Ki 346 microM) and Moloney murine leukemia virus (Ki 112 microM) reverse transcriptases. In addition, cytotoxic and antifungal activities were observed.

The mniopetals, new inhibitors of reverse transcriptases from a Mniopetalum species (Basidiomycetes). I. Producing organism, fermentation, isolation and biological activities.

Six novel enzyme inhibitors of RNA-directed DNA-polymerases of human immunodeficiency-, avian myeloblastosis and murine leukemia viruses were isolated from fermentations of a canadian Mniopetalum species. They were named mniopetals A, B, C, D, E and F. Their structures were elucidated by spectroscopic methods. The compounds, in addition to their inhibitory activities on reverse transcriptases, exhibit antimicrobial and cytotoxic properties.

Rearing Culicoides variipennis sonorensis (Diptera: Ceratopogonidae) on agar and nematodes.

Culicoides variipennis sonorensis Wirth & Jones was reared from egg to adult in petri dishes on a 0.5 or 1% agar substrate with bacterial-feeding nematodes (Pelodera, Panagrellus) as food. All larval stages except the first instar were observed attacking and feeding on nematodes. Developmental rate on agar was approximately 25% slower than that of larvae reared in pans of water with bacteria, fungi, and algae as food. Pupation success was approximately 75% from dishes (3.5 or 9 cm diameter) with 30 and 100 eggs, respectively. The technique has significant advantages for maintainance of small laboratory colonies and allows continuous observation of developing immatures for experimental studies.