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At least 163 records · Page 9Linked to original sources
PubMed1997

Prevalence of rabies in bats in Michigan, 1981-1993.

OBJECTIVES: To analyze the species distribution of animals submitted to the Michigan Department of Public Health (MDPH) for rabies testing during 1993. To determine whether any of the 9 species of bats residing in Michigan carries a disproportionate rabies burden, and to determine whether bats contributed the most cases of confirmed rabies during 1981 through 1992. DESIGN: Epidemiologic study. PROCEDURE: Records of animals submitted to the MDPH for rabies testing during 1993, and between 1981 and 1992, were reviewed. Information regarding type of animal submitted, specific species if the animal was a bat, county from which the animal was obtained, the identity of the submitting individual, species of the animal exposed, month of the submission, and results of rabies testing was extracted from these records. RESULTS: During 1993, the MDPH received 2,045 submissions for rabies testing. Seventeen rabid animals were identified: 1 cat, 1 skunk, and 15 bats. Two hundred forty-six bats were submitted for testing. Eptesicus fuscus, the big brown bat, accounted for 97.2% (239) of bat submissions and was the only species of bat that had positive results of testing for rabies. Annual percentages of submitted bats found to be rabid ranged from 2.0 to 11.0%, with a 13-year mean of 6.2%. CONCLUSIONS: 100% of the confirmed cases of rabies in bats reported in Michigan in 1993 were associated with in E fuscus. During 1981 through 1992, most of Michigan's confirmed cases of rabies in animals developed in bats.

Animals↗
PubMed2001

Cyclodiene insecticide, DDE, DDT, arsenic, and mercury contamination of big brown bats (Eptesicus fuscus) foraging at a Colorado Superfund site.

Rocky Mountain Arsenal (RMA) National Wildlife Area, near Denver, Colorado, is a Superfund site contaminated by past military and industrial uses, including pesticide manufacturing. From an ecosystem standpoint, the most critical contaminants at RMA are certain cyclodiene insecticides and metabolites, p,p'-DDE, p,p'-DDT, arsenic, and mercury. Bats are important ecosystem components that can be impacted by persistent contaminants because of their position in the food chain and their potential longevity and thus duration of exposure. Big brown bats (Eptesicus fuscus) were captured (n = 51) while foraging at RMA in the summers of 1997 and 1998 for determination of concentrations of contaminants of concern in carcasses, brains, and stomach contents. Adult females (n = 15) were also tracked by radiotelemetry to determine locations of nearest maternity roosts for sampling of guano for contaminant analysis and inspection for potential contaminant-induced mortality. Bats captured while foraging at RMA had measurable quantities of dieldrin and DDE in masticated insect samples from stomach contents and significantly higher concentrations of dieldrin, DDE, DDT, and mercury (juveniles) in carcasses than big brown bats (n = 26) sampled at a reference area 80 km to the north. Concentrations of dieldrin and DDE in brains of bats captured while foraging at RMA were also greater than in bats from the reference area, but not high enough to suggest mortality. Maximum concentrations of DDE, DDT, and cyclodienes in brains of big brown bats were found in adult males from RMA. Guano from the two closest known roosts had significantly higher concentrations of dieldrin, DDE, and mercury than guano from two roosts at the reference area. Dieldrin concentrations in carcasses of bats from RMA were highest in juveniles, followed by adult males and adult females. DDE concentrations in carcasses were lowest in adult females at both sites and highest in adult males at RMA. No contaminant-related mortality was obvious at the small maternity colonies near RMA. Big brown bats show higher contamination than most other mammals previously sampled at this site. Concentrations and proportions of samples with detectable residues of dieldrin in carcasses of big brown bats from RMA were similar to or exceeded reports for this species from elsewhere in the United States some 25 years ago, prior to or just following restrictions on use of this compound.

Animals↗
PubMed2007

Seasonal dynamics in the numbers of parasitic bugs (Heteroptera, Cimicidae): a possible cause of roost switching in bats (Chiroptera, Vespertilionidae).

The objective of the present paper is to extend the knowledge of roosting strategies of bats and the interaction of bats with their roost ectoparasites, the bat bugs Cimex pipistrelli. The project was focussed on the potential causality of bat movements and the variation in bug numbers. For 2 years, three model bat boxes with breeding female Pipistrellus pygmaeus were monitored inside floodplain forest. After the arrival of bats in May, adults and first instars of bugs were observed in the boxes. During the lactation period in June, when the bats did not occupy the roosts, the first instar bugs died out followed by the adults. The decrease in bug numbers began only several days after the bats had left the boxes. After a month of the bats' absence, the abundance of adult bugs decreased by half of their number. Only the eggs survived the period when the roosts were unoccupied in summer. In mid-July, after the arrival of lactating females, an increase in the number of bugs was observed. At the beginning of August, however, no new eggs were found. Although adult C. pipistrelli are able to survive the winter period in the boxes, the bats, by shifting the roosts within the vegetation season, prevent the massive reproduction of these parasites.

Animals↗
PubMed2002

Support for the allotonic frequency hypothesis in an insectivorous bat community.

The allotonic frequency hypothesis proposes that certain insectivorous bat species can prey upon moths that can hear bat echolocation calls by using echolocation frequencies outside the sensitivity range of moth ears. The hypothesis predicts that the peak frequencies of bat echolocation calls are correlated with the incidence of moths in the diets of these bats. The aim of this study was to test this prediction on a bat community dominated by bats using low duty cycle echolocation calls, i.e. aerial foraging, insectivorous species using frequency modulated calls. The community consisted of nine species, two molossids, Sauromys petrophillus and Tadarida aegyptiaca, five vespertilionids, Eptesicus capensis, Eptesicus hottentotus, Miniopteris schreibersii, Myotis tricolor, and Myotis lesueuri, one rhinolophid, Rhinolophus clivosus, and one nycterid, Nycteris thebaica. The insect fauna in the habitat used by the bat community was suited to the testing of the allotonic frequency hypothesis because more than 90% of the moths comprising the insect fauna were tympanate. These included Pyralidae (3.8%), Geometridae (44.9%), Notodontidae (3.8%), Arctiidae (4.6%), Lymantriidae (0.8%) and Noctuidae (32.4%). As predicted, peak echolocation frequency was correlated with the incidence of moths in the diets of these nine species (r=0.98, df=7, P<0.01). Furthermore, multivariate analysis revealed that echolocation frequency (t=9.91, n=129, P<0.001) was a better predictor of diet than forearm length (t=5.51, n=129, P<0.001) or wing area (t=-3.41, n=129, P<0.001). This suggests that the selection pressure exerted by moth hearing might have acted directly on call frequency and secondarily on body size and wing morphology, as part of the same adaptive complex. It is unlikely that dietary differences were due to temporal and spatial differences in the availability of prey because the pattern of differences in skull morphology of the nine species supported our dietary analyses. The skull morphology of a bat represents a historical record of the kind of diet it has become adapted to over its evolutionary history. These results suggest that prey defences may mediate other factors structuring bat communities, e.g. competition. Competition may be reduced for those species of bats that can circumvent prey defences.

Acoustics↗
PubMed2006

Epidemiology of bat rabies in Germany.

Rabies in European bats was first reported in Germany in 1954. In concordance with Denmark and the Netherlands, Germany has reported one of the highest numbers (n = 187) of European bat lyssavirus (EBLV)-positive cases in bats in Europe so far (1954-2005). A combined descriptive epidemiological and phylogenetic analysis on bat rabies and prevailing EBLVs is presented, comprising the past 50 years. So far, only the two lineages of EBLV-1 (genotype 5), a and b, have been detected. Although only 50% of the rabies-positive bats have been identified by species, the Serotine bat (Eptesicus serotinus) is the bat species most frequently infected. Single rabies cases have also been detected in a further five indigenous bat species. There is proven evidence for a substantial bias in the frequency of bat rabies cases in the north of Germany, with an endemic cluster in the northwesternmost low-lying plain areas adjacent to the Netherlands and Denmark. Improvements to bat rabies surveillance and research are discussed.

Animals↗
PubMed1994

Capillary-fiber geometry in pectoralis muscles of one of the smallest bats.

We previously reported striking similarities in the structural capacity for O2 flux in the highly aerobic flight muscles of a hummingbird and bat despite their significant differences in capillary-fiber geometry and number, and fiber size. However, the bats of that study (Eptesicus fuscus, BW 15-16 g) were about 5 times larger than the hummingbirds (Selasphorus rufus; BW 3-4 g). In this study, we examined the flight muscle in a bat of approximately the same size as the hummingbird to determine whether features found in the big brown bat would be accentuated or if there would be additional similarities with the hummingbird. The pectoralis muscle of pipistrelle bats Pipistrellus hesperus (BW 3-5 g) was perfusion-fixed in situ, processed for electron microscopy and analyzed by morphometry. Fiber size (group mean +/- SE, 314 +/- 22 microns 2 at 2.1 microns sarcomere length) and capillary geometry (high degree of tortuosity and branching) were remarkably similar to those in pectoralis muscle of the big brown bat. Thus distances from capillaries to the center of the fibers were not reduced in pipistrelle flight muscle (as in hummingbird) nor was capillary tortuosity and branching further increased (compared with big brown bat). Capillary-fiber surface ratio at a given mitochondrial volume/microns length of fiber was high and similar to that in big brown bat and hummingbird, consistent with the idea that the size of the capillary-fiber interface plays an important role in providing the great O2 flux potential in these muscles. In addition, capillary-fiber number at a given fiber mitochondrial volume per micron length of fiber was similar to that in other muscles including big brown bat and hummingbird flight muscle, bat hindlimb and rat M. soleus. This supports the notion of a close relationship between capillary number and mitochondrial volume on an individual fiber basis in aerobic muscles.

Animals↗
PubMed2006

Social transmission of novel foraging behavior in bats: frog calls and their referents.

The fringe-lipped bat, Trachops cirrhosus, uses prey-emitted acoustic cues (frog calls) to assess prey palatability . Previous experiments show that wild T. cirrhosus brought into the laboratory are flexible in their ability to reverse the associations they form between prey cues and prey quality . Here we asked how this flexibility can be achieved in nature. We quantified the rate at which bats learned to associate the calls of a poisonous toad species with palatable prey by placing bats in three groups: (a) social learning, in which a bat inexperienced with the novel association was allowed to observe an experienced bat; (b) social facilitation, in which two inexperienced bats were presented with the experimental task together; and (c) trial-and-error, in which a single inexperienced bat was presented with the experimental task alone. In the social-learning group, bats rapidly acquired the novel association in an average of 5.3 trials. In the social-facilitation and trial-and-error groups, most bats did not approach the call of the poisonous species after 100 trials. Thus, once acquired, novel associations between prey cue and prey quality could spread rapidly through the bat population by cultural transmission. This is the first case to document predator social learning of an acoustic prey cue.

Animals↗
PubMed1987

Respiratory allergy to inhaled bat guano.

In the Sudan many asthmatic patients attribute their symptoms to inhalation of bat droppings. Design of the roofs of many Sudanese buildings allows black bats to roost; guano drops through cracks in the ceiling into the rooms below where it can be inhaled and cause allergic respiratory disorders. Seven atopic patients seen at Sennar Hospital with bat-related case-histories were investigated. Six had bronchial asthma and allergic rhinitis and one had asthma alone. Extracts of yellow hairy bat, black bat, and bat droppings were made. All seven patients had a positive skin prick test and specific IgE antibodies (RAST) to bat droppings. Three patients also had a positive RAST to both yellow and black bats and one patient to yellow bat. Droppings are probably the major allergen source in bat-related respiratory allergy.

Adult↗
PubMed1999

Neutral and stereospecific Tc-99m complexes: [99mTc]N-benzyl-3,4-di-(N-2-mercaptoethyl)-amino-pyrrolidines (P-BAT).

Technetium-99m-labeled radiopharmaceuticals are currently the most commonly used agents in nuclear medicine. To prepare binding site-specific small molecules containing a Tc-99m complexing core, it is important to consider a ligand system, which selectively forms only one stereoisomer. A novel series of bisaminoethanethiol (BAT) derivatives as a model system were prepared. Stereoisomers of N-benzyl-3,4-di(N-2-mercaptoethyl)-amino pyrrolidines (P-BAT): (3R,4R)-P-BAT (R,R-4) and (3,4)meso-P-BAT (8), the trans and meso isomer, respectively, as a chelating group were prepared successfully. The desired Tc-99m P-BAT complexes were obtained by using Sn(II)/glucoheptonate as the reducing agent for [99mTc]pertechnetate. As predicted, after complexation with [99mTc]Tc'O, the trans isomer, (3R,4R)-P-BAT (R,R-4), showed only one isomer; whereas the corresponding meso isomer, (3,4)meso-P-BAT (8), produced two distinctive complexes isolated readily by high performance liquid chromatography (HPLC). The [99mTc](R,S) meso-P-BAT (8) isomers showed a different lipophilicity (partition coefficient [P.C.] = 54.3 and 55.4 for peak A and peak B, respectively), as compared with that of the corresponding [99mTc](3R,4R)-P-BAT (R,R-4), trans isomer (P.C. = 163). Results of the biodistribution study in rats of these isomers show different heart and brain uptake, suggesting that the intrinsic differences in biodistribution are due to structural and stereospecific factors. Examples in this report confirm that it is possible to design stereospecific Tc-99m complexes based on the bisaminoethanethiol (N2S2, BAT) ligand system. Consideration on stereoselectivity of site-specific agents labeled with Tc-99m is likely an essential requirement on developing binding-site specific radiopharmaceuticals.

Animals↗
PubMed1975

Vitamin B12 metabolism in the fruit bat (Rousettus aegyptiacus). The induction of vitamin B12 deficiency and its effect on folate levels.

1. Vitamin B12 metabolism was studied in bats of the species Rousettus aegyptiacus, which live on an all-fruit diet in the wild. 2. There was a wide range in values for the serum vitamin B12 concentration of newly captured bats, but bats captured in the early spring had significantly higher mean serum vitamin B12 levels than bats captured in the early autumn. 3. There was an exponential decrease in serum vitamin B12 concentration with time in captivity for bats fed on a vitamin B12-deficient, all-fruit diet; the biological half-life was 80 d in serum, 109 d in liver and 164 d in kidney. 4. The main storage organ for vitamin B12 in the bats was the liver, mean content 1067 ng vitamin B12. After 50 d, injected [57Co]cyanocobalamin had equilibrated with body vitamin B12 stores, and 17% of the retained radioactivity was present in the liver. From these results it was calculated that the total body vitamin B12 content of the bat was c. 6500 ng. 5. The biological half-life of injected [57Co]cyanocobalamin was 70--88 d and the calculated daily requirement was 50--60 ng (0-2 mug/kg body-weight per d). 6. As serum vitamin B12 levels decreased, serum folate levels increased. The erythrocyte folate concentration increased significantly after 130 d on the all-fruit diet and then decreased to the initial values after 190 d. 7. Vitamin B12 metabolism in the fruit bat is similar in many respects to that of man, but on a 'weight-for-weight' basis the bat has a 5- to 15-fold greater requirement for this vitamin. 8. Vitamin B12 deficiency may be induced fairly rapidly in fruit bats fed on an all-fruit diet.

Animals↗
PubMed2005

Severe acute respiratory syndrome coronavirus-like virus in Chinese horseshoe bats.

Although the finding of severe acute respiratory syndrome coronavirus (SARS-CoV) in caged palm civets from live animal markets in China has provided evidence for interspecies transmission in the genesis of the SARS epidemic, subsequent studies suggested that the civet may have served only as an amplification host for SARS-CoV. In a surveillance study for CoV in noncaged animals from the wild areas of the Hong Kong Special Administration Region, we identified a CoV closely related to SARS-CoV (bat-SARS-CoV) from 23 (39%) of 59 anal swabs of wild Chinese horseshoe bats (Rhinolophus sinicus) by using RT-PCR. Sequencing and analysis of three bat-SARS-CoV genomes from samples collected at different dates showed that bat-SARS-CoV is closely related to SARS-CoV from humans and civets. Phylogenetic analysis showed that bat-SARS-CoV formed a distinct cluster with SARS-CoV as group 2b CoV, distantly related to known group 2 CoV. Most differences between the bat-SARS-CoV and SARS-CoV genomes were observed in the spike genes, ORF 3 and ORF 8, which are the regions where most variations also were observed between human and civet SARS-CoV genomes. In addition, the presence of a 29-bp insertion in ORF 8 of bat-SARS-CoV genome, not in most human SARS-CoV genomes, suggests that it has a common ancestor with civet SARS-CoV. Antibody against recombinant bat-SARS-CoV nucleocapsid protein was detected in 84% of Chinese horseshoe bats by using an enzyme immunoassay. Neutralizing antibody to human SARS-CoV also was detected in bats with lower viral loads. Precautions should be exercised in the handling of these animals.

Amino Acid Sequence↗
PubMed2000

Morphological study of the heart innervation of bats Myotis daubentoni and Eptesicus serotinus (Microchiroptera: Vespertilionidae) during hibernation.

The capability of bats to have heart rates fewer than 10 beats/min during hibernation and greater than 700 beats/min during flight surprises biologists and cardiologists. Cardioacceleration of hibernating bats is considered to be a function of their intracardiac nervous system. In the present study we investigated the morphology of the heart innervation of ten M. daubentoni and four E. serotinus bats during their natural hibernation in order to determine which intracardiac structures may be involved in cardioacceleration during their short-term (in av. 15-30 min) arousal from hibernation. The primary conclusions were as follows: (1) The innervation pattern of bats differs from many mammals in that bats have: (a) a subepicardiac nerve plexus which is vastly developed and contains a large number of intrinsic ganglia on both atria and ventricles, and (b) very small diameter axons within the unmyelinated nerve fibres, from 0.15 to 0.7 microm. (2) During hibernation an intercellular space of the sinoatrial node of M. daubentoni bats was in part filled with a cottony substance which can presumably be considered to be a temporary barrier between the conductive cardiomyocytes and nerve fibres. (3) In the hibernating bats, the acetylcholine vesicles were aggregated in the synaptic bulbs away from the presynaptic membrane. Possibly, the aggregation of the acetylcholine vesicles is capable of modifying cholinergic influences on the heart activity of hibernating bats. (4) The dense cores of catecholamine synaptic vesicles within, adrenergic axon terminals were seldomly observed in hibernating bats. Therefore, catecholamines probably do not play a crucial role in the cardioacceleration of hibernating bats.

Animals↗
PubMed1969

Echo-location of bats after ablation of auditory cortex.

1. Echo-location of blinded Yuma bats (Myotis yumanensis) was studied after ablation of the auditory cortex (A.C.). A task of obstacle-avoidance was given to the bats. Hits and misses of strands were counted, and orientation sounds emitted by the bats during flight were recorded.2. After bilateral ablation of A.C., two bats out of six failed to avoid even large obstacles such as 3.7 mm strands and wall. These bats emitted orientation sounds at a rate of 10-15/sec during flight, but did not change that rate before crossing the obstacles and crashed into them. In these bats, other cortical areas in addition to A.C. were probably ablated.3. In three bats out of six, obstacle-avoidance performance was quite normal. These bats avoided even 0.2 mm strands with orientation sounds, the repetition rate of which was systematically increased before crossing the obstacles. In two of them, the dorsal half of the inferior colliculus (I.C.) was bilaterally ablated in addition to A.C. But ability to avoid the obstacles was not impaired at all. Their cerebral cortices did not show the normal positive-negative diphasic potential change in response to tonal stimuli, although the normal diphasic potential change was retained in A.C. of bats which could not echo-locate as a result of bilateral ablation of the main nucleus of I.C. A.C. appeared to be not essential for echo-location.4. Unilateral ablation of A.C. and the internal capsule had no effect on echo-location, but bilateral ablation of them usually resulted in death from operational trauma.5. It was suggested that A.C. was less important for sound localization in bats than in cats.

Journal Article↗
PubMed1988

Delay-tuned combination-sensitive neurons in the auditory cortex of the vocalizing mustached bat.

1. FM-FM neurons in the auditory cortex of the mustached bat are sensitive to a pair of frequency-modulated (FM) sounds that simulates an FM component of the orientation sound and an FM component of the echo. These neurons are tuned to particular delays between the two FM components, suggesting an encoding of target range information. The response properties of these FM-FM neurons, however, have previously been studied only with synthesized orientation sounds and echoes delivered from a loud-speaker as substitutes for the bat's own orientation sounds and corresponding echoes. In this study, the combination sensitivity and delay tuning of FM-FM neurons were examined while the bat was actively vocalizing. 2. When the bat produced orientation sounds in an anechoic environment, or synthesized single FM echoes were delivered to a silent bat, the FM-FM neurons showed weak or no response. In contrast, when synthesized FM echoes were delivered with a particular delay from the FM component of the vocalized orientation sounds, the FM-FM neurons exhibited strong facilitative responses. 3. In both the vocalizing bats and the silent bats with substituted synthesized orientation sounds, all FM-FM neurons tested responded preferentially to the same echo harmonic (FM2, FM3, or FM4). 4. In vocalizing bats, FM-FM neurons showed maximum response to an echo FM component delivered with a particular delay (best delay) from an FM component in the orientation sound. Best delays measured with vocalized orientation sounds were nearly the same as those measured with synthesized orientation sounds. 5. The equivalent effect of a vocalized orientation sound and a synthesized FM1 component on the activity of FM-FM neurons indicates that, during echolocation, the FM1 component in the vocalized orientation sound stimulates the auditory system and conditions the FM-FM neurons to be sensitive to echoes with particular delays from the vocalized orientation sounds. 6. The amount of vocal self-stimulation to the inner ear by the bat's own vocalized sounds was measured by recording cochlear microphonic potentials (CMs). Spectral analysis of CM indicated that the amount of vocal self-stimulation by each harmonic of an orientation sound was equivalent to a sound of 70 dB sound pressure level (SPL) for the first harmonic (H1), 91 dB SPL for H2, 83 dB SPL for H3, and 70 dB SPL for H4, when the amplitude of the vocalized sound was 117 dB SPL at 5 cm in front of the bat's mouth.

Animals↗
PubMed2005

Echolocating bats can use acoustic landmarks for spatial orientation.

We investigated the echolocating bat's use of an acoustic landmark for orientation in a complex environment with no visual information. Three bats of the species Eptesicus fuscus were trained to fly through a hole in a mist net to receive a food reward on the other side. In all experiments, the vocal behavior of the bats was recorded simultaneously using a high-speed video recording system, allowing for a 3D reconstruction of the flight path. We ran three types of experiments, with different spatial relations between the landmark and net hole. In the first experiment, the bat's behavior was studied in test trials with the landmark placed 10 cm to the left of the net opening; between test trials, the positions of the net opening and landmark were moved, but the spatial relationship between the two remained fixed. With the landmark adjacent to the net opening, the bats quickly found the hole. In the second experiment, bats were tested in control trials in which the landmark was moved independently of the hole, breaking the established spatial relationship between the two. In control trials the bats repeatedly crashed into the net next to the landmark, and inspected the area around it. In the final experiment, the landmark was removed altogether from the set-up. Here the bats spent more time per trial searching for the net opening with an increased number of inspections as well as crashes into the net. However, over the course of a test day without the landmark, bats reduced the time spent per trial and focused inspections and crashes around the hole. The behavioral data show for the first time that the echolocating bat can learn to rely on an acoustic landmark to guide spatial orientation.

Animals↗
PubMed2005

The adaptive function of tiger moth clicks against echolocating bats: an experimental and synthetic approach.

We studied the efficiency and effects of the multiple sensory cues of tiger moths on echolocating bats. We used the northern long-eared bat, Myotis septentrionalis, a purported moth specialist that takes surface-bound prey (gleaning) and airborne prey (aerial hawking), and the dogbane tiger moth, Cycnia tenera, an eared species unpalatable to bats that possesses conspicuous colouration and sound-producing organs (tymbals). This is the first study to investigate the interaction of tiger moths and wild-caught bats under conditions mimicking those found in nature and to demand the use of both aerial hawking and gleaning strategies by bats. Further, it is the first to report spectrograms of the sounds produced by tiger moths while under aerial attack by echolocating bats. During both aerial hawking and gleaning trials, all muted C. tenera and perched intact C. tenera were attacked by M. septentrionalis, indicating that M. septentrionalis did not discriminate C. tenera from palatable moths based on potential echoic and/or non-auditory cues. Intact C. tenera were attacked significantly less often than muted C. tenera during aerial hawking attacks: tymbal clicks were therefore an effective deterrent in an aerial hawking context. During gleaning attacks, intact and muted C. tenera were always attacked and suffered similar mortality rates, suggesting that while handling prey this bat uses primarily chemical signals. Our results also show that C. tenera temporally matches the onset of click production to the ;approach phase' echolocation calls produced by aerial hawking attacking bats and that clicks themselves influence the echolocation behaviour of attacking bats. In the context of past research, these findings support the hypotheses that the clicks of arctiid moths are both an active defence (through echolocation disruption) and a reliable indicator of chemical defence against aerial-hawking bats. We suggest these signals are specialized for an aerial context.

Adaptation, Physiological↗
PubMed2002

After-effects of using a weighted bat on subsequent swing velocity and batters' perceptions of swing velocity and heaviness.

In baseball and softball, warm-up swings with a weighted bat have been believed to increase swing velocity when an ordinary bat is used in the subsequent competitive situation. The purpose of this study was to investigate the after-effects of using a weighted bat on subsequent swing velocity and batters' perceptions of swing velocity and heaviness. Eight men in varsity softball and baseball hit a ball suspended from the ceiling 45 times (3 sets of 15 trials). For each set, the initial 5 trials were done using an ordinary 920-g wooden bat (Control condition), and the following 5 trials by a bat with an 800-g bat ring (Weighted condition), and the final 5 trials again by the ordinary bat (post-Weighted condition). Analysis of variance showed a significant decrease of 3.3% in the measured linear velocity of the bat prior to impact with the ball for the first swing of the post-Weighted condition compared with the Control condition. From the second swing the velocity returned to the level of the Control condition. Subjective judgment of the heaviness and velocity of swings for the Weighted and post-Weighted conditions by each participant showed that the ordinary bat felt lighter and swing speed felt faster for the post-Weighted condition. The advantage of the warm-up with a weighted bat was thus psychological and not biomechanical.

Adult↗
PubMed2001

Treatment with BAT monoclonal antibody decreases tumor burden in a murine model of leukemia/lymphoma.

BAT is a monoclonal antibody produced against membranes of Daudi cells that induces anti-tumor activity in mice against a variety of solid murine and human tumors, mediated by its immune stimulatory properties on murine and human lymphocytes. The present study analyzes the effect of BAT on leukemia/lymphoma using the BCL1 model of leukemia/lymphoma in BALB/C mice. BAT antibody binds to BCL1 leukemia cells and recognizes a 48 kDa protein similar to the antigen on Daudi cells. Mice inoculated with leukemia cells were treated either by direct BAT injections or by adoptive transfer of lymphocytes from BAT-injected mice. Administration of BAT monoclonal antibody was either once, on day 14, or daily on days 10-13 post tumor inoculation. A single injection of BAT resulted in reduction of peripheral blood tumor cells, however additional injections further decreased the tumor cell number reaching a 95-fold reduction on day 20 post tumor inoculation. Anti-tumor effect was also obtained when animals were injected with splenocytes from BAT-treated donor mice. A significant prolongation of survival of BAT-treated mice was observed although with no cure. The results of this study indicate that BAT might be used for reducing the tumor burden in leukemia for immunotherapy and in combination with other treatment modalities.

Adoptive Transfer↗