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D Stiller

Publications and source records attributed to D Stiller.

At least 37 records · Page 2Linked to original sources
PubMed1995

Conserved recombinant antigens of Anaplasma marginale and Babesia equi for serologic diagnosis.

The competitive inhibition ELISA (CI-ELISA) format overcomes problems associated with antigen purity since the specificity of the CI-ELISA depends solely on the monoclonal antibody (mAb) used. Therefore, the CI-ELISA format is well suited for use with recombinant antigens. Molecular clones expressing a conserved 19 kDa protein of Anaplasma marginale and a 34 kDa protein of Babesia equi were derived and characterized. The 19 kDa A. marginale protein, conserved in all recognized Anaplasma species, and present in the infected tick salivary gland, was reactive with all bovine immune sera tested. The 34 kDa B. equi protein contains a protein epitope bound by antibody in equine immune sera from 19 countries. Monoclonal antibodies reactive with these proteins were derived and applied with recombinant copies of the 19 kDa A. marginale and 34 kDa B. equi proteins in a CI-ELISA format.

Amino Acid Sequence↗
PubMed1995

Recent developments in elucidating tick vector relationships for anaplasmosis and equine piroplasmosis.

This brief review focuses first on several epidemiologically relevant aspects of anaplasmosis, including: (1) the role of male ticks as intrastadial, biological vectors of Anaplasma through interhost transfer; (2) the application of molecular diagnostic assays in assessing tick vector competence and evaluating the role of chronically infected carrier cattle as sources of Anaplasma marginale infection in vector ticks; (3) opportunities provided by a recently developed in vitro tick feeding system in quantitating studies of tick-hemoparasite-host interactions. Lastly, current knowledge of the status of New World ticks as experimental and/or natural vectors of equine piroplasms is discussed.

Anaplasmosis↗
PubMed1994

Magnetic resonance imaging-controlled laser-induced interstitial thermotherapy.

RATIONALE AND OBJECTIVES: Laser-induced interstitial thermotherapy (LITT) may become an attractive modality for minimally invasive tumor therapy. Magnetic resonance imaging (MRI) could be used to assist this procedure. METHODS: A T1-weighted turbo fast low-angle shot (FLASH) sequence for on-line monitoring of the laser-influenced region (liver, muscle) was investigated. Sequence parameters were optimized for maximal image contrast. Magnetic resonance imaging-controlled LITT was performed in vitro, in vivo (rabbits), and in 8 human investigations (6 patients). Special laser applicators were used to establish a uniform laser light distribution. RESULTS: With the MRI sequence used, the LITT region is visualized as a bright area outlined by a dark border. This dark border corresponds to an isotherm of 45 +/- 2 degrees C depending on the sequence parameters used. CONCLUSION: With the T1-weighted turbo-FLASH sequence, MRI can be used for on-line monitoring of interstitial laser-induced thermotherapy in moving organs.

Aged↗
PubMed1994

Molecular and biological characterization of a newly isolated Anaplasma marginale strain.

Anaplasma marginale, a rickettsial hemoparasite of cattle and other ruminants, results in significant economic losses worldwide. Distinct strains of A. marginale have been identified based on differences in tick transmissibility, molecular size of surface proteins and DNA restriction fragments, and reactivity to a panel of monoclonal antibodies. These different strains vary considerably in their virulence, antigenic composition, and ability to protect against heterologous challenge. In this paper, we report on the molecular characterization of a newly isolated strain of A. marginale, designated St. Maries, recovered from an acutely infected cow in northern Idaho. Dermacentor andersoni ticks taken from the infected animal were tested for infection by RNA probe analysis. The infection rate of male ticks (as determined by midgut infection) was 100%, and the infection rate of female ticks was 83%. Infected male ticks were able to transmit the St. Maries strain to a susceptible calf. The high infection rate in male ticks may be particularly relevant, given that male ticks are believed to be epidemiologically important in transmission of A. marginale because of their intermittent feeding behavior, which promotes interhost transfer. The newly isolated strain differs from other US strains, including strains previously isolated in Idaho and Washington, based on reactivity to a panel of monoclonal antibodies and restriction fragment length polymorphisms. These results imply that antigenically distinct strains of A. marginale may arise within the same region.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaplasma↗
PubMed1993

Primary retroperitoneal mucinous cystadenomas with gastric epithelial differentiation.

We present two rare cases of retroperitoneal mucinous cystadenomas (RMC) by clinical data, light microscopy, electron microscopy, histochemistry, and immunohistochemistry. Both tumors occurred in women. We excluded attachment to any organ. Additional immunohistochemical examinations were performed for comparison in 10 cases of ovarian mucinous cystadenomas (OMC). Both RMC showed no significant immunohistochemical differences from the OMC. Ultrastructurally and histologically the RMC resemble OMC reported in the literature. Immunohistologically, we proved gastric epithelial differentiation by using one monoclonal antibody (2B5) recognizing gastric mucin and one polyclonal antibody against pepsinogen II (PG II). In spite of this, the histogenesis of RMC in the presented cases in the end remains uncertain.

Adult↗
PubMed1993

Ischemia tolerance of free-muscle flaps: an NMR-spectroscopic study in the rat.

The ischemia tolerance of free-muscle flaps was investigated in the rat by orthotopic and syngeneic transplantation of muscle flaps measuring 4 x 2.5 cm. The effects of ischemia with a maximal duration of 7 hours on the raised flaps and of anoxia caused by occlusion of the flap vessels were studied for the first time using 31P-spectroscopy. Energy metabolism was found to recover fast after 3 hours of ischemia, whereas a duration of 4 hours led to severe, only slowly reversible changes. Longer periods of ischemia resulted in a complete loss of energy reserves (PCr) and weaker ATP signal. The complete absence of ATP and a pH value under 6 indicated irreversible muscular damage.

Abdominal Muscles↗
PubMed1993

Impact of persistent Anaplasma marginale rickettsemia on tick infection and transmission.

Anaplasma marginale, an intraerythrocytic rickettsia of cattle, is transmitted biologically by ticks. Because of the brevity of acute A. marginale infection, transmission may rely on the tick's ability to acquire the organism from persistently infected cattle with low rickettsemia levels. By using a nucleic acid probe to quantitate low-level infection, we found that rickettsemia levels in persistently infected cattle fluctuated at approximately 5-week intervals during a 24-week period, from < 10(4) infected erythrocytes per ml of blood to high levels of approximately 10(7) infected erythrocytes per ml of blood. Cattle maintained very low rickettsemia levels (< 10(4.3) infected erythrocytes per ml of blood) for approximately 4 to 8 days of every 5-week cycle. The effect of fluctuations in rickettsemia in persistently infected cattle on acquisition by Dermacentor andersoni nymphal and adult male ticks was examined. A positive correlation was observed between rickettsemia levels in cattle and the resulting infection rates of ticks. At high rickettsemia levels, up to 80% of ticks acquired infection, but even at extremely low rickettsemia levels, 27% of adult male ticks became infected. Moreover, once ticks acquired infection, biological replication of the organism within the ticks appeared to make up for initial differences in the infecting dose. The high infection rates in adult males, combined with their intermittent feeding behavior and the observation that only a few infected ticks were required for transmission to a susceptible host, suggest that adult male D. andersoni ticks are epidemiologically important in A. marginale transmission. Because cattle with all levels of rickettsemia were capable of efficient transmission to ticks, population control efforts must include decreasing transmission from persistently infected individuals.

Anaplasma↗
PubMed1993

Characterization of an Anaplasma ovis isolate from desert bighorn sheep in southern California.

To understand the role of bighorn sheep (Ovis canadensis) in the epidemiology of anaplasmosis, we recovered a field isolate from a suspected enzootic area in southern California (USA). Whole blood was collected from three desert bighorn sheep (Ovis canadensis nelsoni) and inoculated into a susceptible splenectomized domestic sheep, calf and a susceptible spleen-intact bighorn sheep. No infection occurred in the calf, but a detectable infection developed in both the domestic sheep and bighorn sheep 24 days after inoculation. The infection in both domestic and bighorn sheep resulted in severe clinical disease but was resolved with the use of tetracycline. Using monoclonal antibodies and DNA probes, we confirmed that the isolate was Anaplasma ovis.

Anaplasma↗
PubMed1993

A retrospective serologic survey for Anaplasma spp. infection in three bighorn sheep (Ovis canadensis) populations in California.

Using an indirect immunofluorescence assay, we determined the prevalence of Anaplasma-reactive antibody in three herds of bighorn sheep, each a different subspecies and occupying a different habitat in California (USA). Antibodies to Anaplasma spp. were identified in none of twenty California bighorn (Ovis canadensis californiana) sampled from the Mt. Baxter herd, 11 of 17 peninsular bighorn (O. canadensis cremnobates) sampled in the Santa Rosa Mountains, and all 20 desert bighorn (O. canadensis nelsoni) sampled at Old Dad Peak/Kelso Mountains. Based on an assay and an adsorption technique, the titers most likely were due to Anaplasma ovis. The presence and species of tick vectors in each of the habitats, and the presence or absence of deer or livestock were identified as factors potentially influencing seroprevalence of antibodies.

Adsorption↗
PubMed1993

Detection and localization of perfluorodecalin in the human eye by fluorine 19 magnetic resonance.

Perfluorocarbons are applied as heavy liquids during vitreoretinal surgery. They are removed again intraoperatively because of possible harmful long-term effects. Following vitreoretinal surgery, residual perfluorodecalin (PFD) was detected in four eyes and localized in two others by fluorine 19 magnetic resonance (19F-MR). In vitro analysis of 19F-MR spectra shows that chemical shift artifacts can be avoided much better with PFD than with perfluorotributylamine and perfluoroctane. Therefore, PFD localization by 19F-MR imaging is superior to that of perfluorotributylamine and perfluoroctane. This examination can be performed on currently employed magnetic resonance imaging systems equipped with a fluorine channel. In the event of significant inadvertent residual quantities of PFD and obscured media, 19F-MR may specifically detect and localize PFD.

Aged↗
PubMed1993

Development of Anaplasma marginale in salivary glands of male Dermacentor andersoni.

Development of the rickettsia, Anaplasma marginale, in salivary glands of male Dermacentor andersoni exposed as nymphs or adult ticks, was studied indirectly by inoculation of susceptible calves with homogenates and directly by examination, using light microscopy and a DNA probe; some unfed ticks were incubated before tissues were collected. Salivary gland homogenates made from ticks in every treatment group caused anaplasmosis when injected into susceptible calves; prepatent periods decreased as the time that ticks had fed increased. Colonies of A marginale were seen only in salivary glands of ticks exposed as adults and not in those exposed as nymphs; the percentage of salivary gland acini infected in these ticks increased linearly with feeding time. However, the probe detected A marginale DNA in salivary glands of ticks from both groups; the amount of DNA detected increased as feeding time was extended. The amount of A marginale DNA appeared to remain constant in gut tissues, but to increase in salivary glands. Salivary glands of adult-infected male ticks that were incubated, but did not feed a second time, became infected with A marginale, and the pattern of infection of acini varied with incubation temperature. Development of A marginale in salivary glands appears to be coordinated with the tick feeding cycle; highest infection rate was observed in ticks exposed as adults.

Anaplasma↗
PubMed1993

[Chemoembolization of liver tumors (VX-2) using lyophilized Spherex].

Chemoembolisation is a new promising approach. Until now no standardized procedures exist for the production of the embolisate-cytostatics mixture. A main technical problem when doing chemoembolisation is the proof of the complete peripheral vascular occlusion. By using lyophilized Spherex and cytostatics, diluted in x-ray contrast media, frozen pictures can be obtained and the complete proof of the embolisation is possible. Therefore the conventional x-ray examination can be used to monitor the embolisation treatment instead of the much more sophisticated DSA technique.

Animals↗
PubMed1992

Babesia bigemina: quantitation of infection in nymphal and adult Boophilus microplus using a DNA probe.

Candidates for a subunit vaccine against bovine babesiosis include surface proteins of infective forms found in the salivary glands of tick vectors. However, low numbers of infective forms are present within ticks and hinder analysis of this stage. To solve this problem, conditions which yield high numbers of infective forms were investigated with the use of a Babesia bigemina-specific DNA probe. DNA from progeny of female Boophilus microplus infected with B. bigemina was hybridized to probe DNA to detect and quantitate infection. There was no difference in the prevalence of infection in progeny of three strains of Bo. microplus. However, within a strain, prevalence could be increased to 30% by combining selection of progeny from heavily (3+) infected female ticks and selection of eggs laid 120 hr postengorgement. Quantitation of infective forms within pooled salivary gland preparations of 10 infected nymphal and adult Bo. microplus demonstrated that Day 9 and 10 nymphal ticks contained the highest numbers of parasites and represented approximately 10(6) infective forms. This number of infective forms is suitable for isolation and further characterization.

Animals↗
PubMed1992

Electron microscopic and 31-P NMR studies of ischemic injured rat livers during preservation and reflow.

Ischemic injury induced during preservation and reperfusion contributes to post-operative failure in liver transplantation. Hepatic injury and recovery from preservation was studied in an isolated rat liver model reperfused with oxygenated erythrocytes. In order to correlate morphological and functional findings, 31-P nuclear magnetic resonance spectroscopy and electron microscopy were used to investigate metabolic and ultrastructural changes during 6 hours of reperfusion. Following cold preservation, EM's showed a primary sinusoidal cell injury, whereas the hepatocytes were well maintained. During reperfusion, hepatocytes displayed further damage. The simultaneous presence of vacuolarly degenerated mitochondria and mitochondria of increased activity was noted. 31-P NMP spectra demonstrated initially a partial ATP-recovery. The maximum level of 60% of the control ATP-value could not be further increased. EM and 31-P NMR indicate that the progressive injury to the liver is due to microcirculatory malfunction induced by an endothelial cell damage, followed by injured hepatocytes themselves, and the consequent intracellular energy crisis that is produced.

Animals↗
PubMed1992

Functional aspects of free muscle transplantation: atrophy, reinnervation, and metabolism.

The atrophy, reinnervation, and metabolism of free muscle flaps were studied in a rat model, by syngeneic and orthotopic transplantation of abdominal wall muscle flaps with neurovascular anastomoses. The three parameters were examined at different time periods, using electrophysiologic and 31-P-spectroscopic measurements. Results show that a certain degree of atrophy (one-fifth of the original volume) must be expected, even when new axons grow throughout the nerve. This is explained by the early reduction of flap metabolism, leading to a loss of parenchyma until neuromuscular conduction is restored. As the maximum duration of ischemia is 2 hr, muscular damage due to reduced metabolism was not produced.

Abdominal Muscles↗
PubMed1992

Development of Anaplasma ovis (Rickettsiales: Anaplasmataceae) in male Dermacentor andersoni (Acari: Ixodidae) transferred from infected to susceptible sheep.

The development of Anaplasma ovis was studied in Dermacentor andersoni males transferred from infected to susceptible sheep. Laboratory-reared male D. andersoni were allowed to feed for 6 d on a sheep with ascending A. ovis parasitemia. The ticks were removed and held at room temperature in a humidity chamber for 6 d, after which they were allowed to feed on five susceptible sheep for 1, 3, 5, 7, or 9 d. Gut and salivary glands were collected from ticks during the 21-d experiment and examined with light and electron microscopy. Anaplasmosis developed in all susceptible sheep. Colonies of A. ovis were first observed in midgut epithelial cells on the 3rd d ticks fed on the infected sheep, and infection persisted in gut cells throughout the experiment. The first colonies contained one large organism that subsequently gave rise to many reticulated ones, which became electron dense over time. After ticks were transferred to susceptible sheep and began the second feeding, individual A. ovis organisms were found from days 3-9 in muscle cells on the hemocoel side of the gut basement membrane. However, colonies did not develop in these cells, and the host cells did not hypertrophy as did cells similarly infected with A. marginale. A final site of development of A. ovis was in salivary glands. Individual organisms were first seen in acinar cells on the first day that ticks fed on the second calves, and salivary gland infections persisted throughout the 9-d feeding period. Colonies of A. ovis developed in salivary gland acinar cells and organisms within these colonies were initially electron lucent but became electron dense. Multiple colonies often were observed within salivary gland cells and often contained organisms in various stages of development.

Anaplasma↗
PubMed1992

Persistence of Anaplasma marginale (Rickettsiales: Anaplasmataceae) in male Dermacentor andersoni (Acari: Ixodidae) transferred successively from infected to susceptible calves.

The persistence of Anaplasma marginale Theiler in male Dermacentor andersoni Stiles ticks exposed to the organism as adults was studied as the ticks were successively transferred to five susceptible calves. All calves fed upon by these ticks rapidly developed clinical anaplasmosis; incubation periods of infection ranged from 19 to 26 d and did not change significantly with successive feedings. Development of A. marginale in tick midgut and salivary glands was followed daily during tick feeding (total, 35 d) with light microscopy and DNA hybridization. With microscopy, A. marginale colonies persisted in midgut cells throughout the experiment. Large colonies were observed in gut muscle cells on days 8 through 35 and were the predominant infected cell type during this part of feeding. Colonies were seen in salivary gland acini from day 2 throughout the 35-d experiment. The DNA probe confirmed the presence of Anaplasma DNA in midgut and salivary glands throughout the experiment. Quantitative estimates of infection intensity in tissues of individual ticks approximated 10(7) initial body equivalents, confirming heavy infections. A marginale in midgut tissues decreased with feeding time, whereas the estimated number of organisms in salivary glands remained constant. These data demonstrate that D. andersoni males are efficient vectors of A. marginale and may be potential reservoirs of infection for ruminants for extended periods.

Anaplasma↗