[New practice guidelines for abortion in cattle due to Neospora caninum?].
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Biomedical subjects
Publications and source records attributed to T Dijkstra.
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Three ELISAs for the detection of antibodies against Neospora caninum in bulk milk were evaluated in 162 Dutch dairy herds. The first ELISA was the Dutch Animal Health Service (AHS) in-house ELISA, developed from the routine in-house serum ELISA. The other two ELISAs were commercial milk ELISAs from IDEXX and LSI. Blood samples of all lactating cows in 162 dairy herds were tested using the AHS in-house serum ELISA. Based on previous studies in the Netherlands a within-herd N. caninum seroprevalence of 15% was associated with increased risk for reproductive losses. This percentage was therefore used as positive seroprevalence cut-off value. Repeatability of the ELISAs was evaluated by testing on three different days. The AHS in-house ELISA lacked specificity, probably due to use of a different batch of antigen on the second and third test-day. Cut-off values were determined using misclassification costs term calculations. At cut-off values 0.6 for the IDEXX and 0.2 for the LSI, a herd sensitivity of 61% (95% CI: 49--73%) and 47% (95% CI: 35--60%) was estimated. Herd specificity at these cut-off values was 92% (95% CI: 87--98%) for the IDEXX and 94% (95% CI: 90--99%) for the LSI ELISA. The positive and negative predictive values were 84% (95% CI: 68--100%) and 86% (95% CI: 79--94%) for the IDEXX ELISA, and 85% (95% CI: 67--100%) and 82% (95% CI: 74--90%) for the LSI ELISA. The agreement between all possible combinations of test-days was expressed by kappa values. These were found to be slightly higher for the IDEXX than for the LSI ELISA. It is concluded that both commercial ELISAs performed satisfactorily to detect a within-herd seroprevalence of N. caninum in lactating cows of at least 15%.
Three children, 2 boys aged 5 and 4 years, and 1 girl aged 2 years, who suffered from intestinal failure as a result of a short bowel syndrome and who were dependent on total parenteral nutrition (TPN), were screened for small bowel transplantation. The girl also had progressive liver failure. Each child had a clear indication for either isolated small bowel or combined small bowel/liver transplantation. All three children were enrolled in an intestinal rehabilitation program because they were referred early. The intestinal rehabilitation consisted of a systematic analysis of the absorptive capacity of the residual intestine, optimizing enteral and parenteral feeding, prevention of catheter sepsis and further deterioration of liver function. The rehabilitation was performed in an in-patient setting. All three children were partially weaned from TPN, while their growth improved. None of the children were consequently listed for small bowel transplantation. When a child is initially referred for small bowel transplantation, intestinal rehabilitation should be considered as part of an intestinal transplantation program.
Eighteen dairy herds with neosporosis-associated abortions were analysed for antibodies against Neospora caninum. Blood samples of all cows, heifers and calves were collected on the same day for each farm. A total of 2430 heads of cattle were examined. For each herd, the seropositive and seronegative animals were plotted against month of birth. Analysis of seroprevalence in relation to age showed an equal distribution of seropositives in all age-groups in 10 herds. In contrast, in eight herds an age-group could be identified which had a significantly higher seroprevalence than the other animals in the herd. Most seropositive animals in the high seroprevalence age-groups had either seronegative dams or seronegative offspring, whereas there was a strong relationship between the serostatus of dams and offspring in the other animals in the herd. Aborting animals were mainly part of the high seroprevalence age-group. These findings strongly indicate a post-natal infection of the animals in the high seroprevalence age-groups, probably due to a point source exposure to N. caninum.
An experiment was carried out to determine whether bovine colostrum or placenta could be a source of infection of Neospora caninum for dogs. For this purpose, two dogs were fed bovine colostrum to which culture-derived N. caninum tachyzoites were added and two other dogs were fed placental cotyledonary tissue from N. caninum seropositive cows. One dog served as a negative control during the start of the experiment but this control dog was fed cotyledonary tissue later on. None of the dogs did produce serum antibodies to N. caninum. All three dogs that were fed cotyledonary tissue did shed N. caninum oocysts, but no oocyst shedding was seen in the two dogs that were fed colostrum with N. caninum tachyzoites. Oocyst excretion did not resume in two dogs after repeated feeding of N. caninum infected placenta. The identity of the oocysts was confirmed by a bioassay in gerbils. It is concluded that ingestion of bovine placenta by dogs is an effective mode of transmission of N. caninum from cattle to dogs.
We reviewed 48 arthrodeses of the carpometacarpal joint of the thumb in 39 patients being treated for osteoarthritis. The mean follow-up period was 90 months (range 14 months-17 years). In 28 (58%) hands pain relief was excellent and in 6 (12%) good. Morbility was significantly reduced (p < 0.002). Mean key pinch (52.9 N) and grip strength (219.5 N) were comparable with the unoperated hand (51.0 and 239.1 N, respectively). Hand function was near normal. In 29 hands an additional operation was needed to remove the osteosynthesis material; 14 hands failed to unite. Osteoarthritis of the scaphotrapezial joint increased significantly faster in the operated hands than in the unoperated ones (p < 0.0001). A soft tissue procedure (such as flexor carpi radialis interposition arthroplasty) is advised instead of arthrodesis, because of the large number of reoperations, based on non-union and removal of the osteosynthesis material. From a survey of published papers we conclude that arthrodesis of the carpometacarpal joint of the thumb can best be done by stapling and bone grafting.
Several studies have found effects of orthographically related masked nonword primes on lexical decisions to target words. These effects have been explained by the neighborhood characteristics of the target word (Forster, 1987), but the neighborhood characteristics of the prime in combination with the target are also found to be important (Hinton, Liversedge, & Underwood, 1998). In this study, we present a new account of masked form-priming effects based on the shared neighborhood of prime and target. Shared neighbors are words that are activated by both prime and target. According to the interactive activation model (McClelland & Rumelhart, 1981), shared neighborhood determines the size of priming effects. This prediction was tested and confirmed in a masked priming experiment that manipulated the shared neighborhood density of complete primes.
Neospora caninum is an intracellular protozoan parasite that was discovered in a dog in 1988. Since then, N. caninum has been demonstrated in a variety of animal species and it has been recognized as an important cause of abortion in cattle. An infection with N. caninum can be maintained in cattle herds for several generations by transplacental transmission from cow to calf. Recently, it was demonstrated that dogs can act as definitive hosts of N. caninum and therefore may be a source of infection for other species by shedding oocysts. Further evidence of a role of the dog in spreading the infection to cattle has been derived from epidemiological studies. The present state of knowledge is reviewed in this paper.
Phonological consistency describes to what extent a letter string in one word is pronounced equally in other words. Phonological reliability describes to what extent a sublexical unit is usually consistent throughout a language. The relationship between the two concepts was investigated by comparing five sublexical units (onset-consonants, vowel, end-consonants, and the concatenation of the vowel with begin- or end-consonants) in Dutch and English with respect to their reliability and to how their consistency was related to naming errors and latencies. In a regression analysis, naming latencies and errors on genuine Dutch words (consistent) and imported words (inconsistent) were predicted by the phonological consistency of the five units. The same was done for two sets of English naming data. Consistency had a much stronger effect in Dutch than in English naming studies when all five units were considered. The special role of the vowel plus end-consonants, which has been found in English naming data, could not be demonstrated in Dutch. In both languages, the size of consistency effects mirrors the reliability of the five units.
Dogs from dairy farms with a known prevalence of Neospora caninum antibodies in the cattle were examined for the presence of N. caninum antibodies using an ELISA. Data of farm dogs were compared with those of dogs examined at a university clinic, which originated mainly in urban areas. Of the 152 farm dogs, 36 (23.6%) were seropositive to N. caninum, which was significantly higher than the proportion of seropositives in the clinic dog population (19 of 344, 5.5%). Seroprevalence was significantly higher (P = 0.01) in female dogs than in male dogs. Seroprevalence in dogs increased with age, indicating postnatal infection. Seropositivity to N. caninum in farm dogs was strongly correlated with a high prevalence of N. caninum antibodies in the cattle. At farms where no dogs were present, the seroprevalence to N. caninum in the cattle was significantly lower (P = 0.0002) than in farms where dogs were present. These findings suggest that there is a relationship between N. caninum infection of farm dogs and cattle. Since dogs have been shown to be definitive hosts of N. caninum, cattle may be infected by exposure to canine oocysts. Further research is needed to find out whether and how dogs may acquire the infection from cattle.
This study describes an outbreak of bovine herpesvirus 1 (BHV1) infections in a dairy herd with special reference to disease symptoms, reproductive performance and milk production losses. The study was carried out with a dairy herd consisting of 98 lactating animals. All animals were housed in the same freestall barn with intensive contact between all animals. An outbreak of BHV1 was induced by injecting three seropositive cows with dexamethasone. During the outbreak, no clinical signs were observed in any of the newly infected animals. At the time of infection, a significant drop in milk production was noted in animals that were initially-seronegative. The production loss was estimated at approximately 9.5 1 per infected animal during the infectious period of 14 days. None of the pregnant cows aborted because of BHV1 infection. During 50 days before BHV1 circulation, there was a significant decrease in the number of successful inseminations in both seronegative and seropositive animals. Therefore, it is doubtful that early pregnancies were terminated by BHV1 infection. The proportion of successful inseminations during the BHV1 circulation in this herd, and in the period thereafter, did not significantly differ from the baseline period.
Light touch contact of a fingertip to a stationary surface provides orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip lead to sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, the coupling of postural sway to a moving contact surface was investigated in detail. Head, center of mass, and center of pressure displacement were measured as the contact surface moved rhythmically at 0.1, 0.2, 0.4, 0.6, and 0.8 Hz. Stimulus amplitude decreased with frequency to maintain peak velocity constant across frequency. Head and body sway were highly coherent with contact surface motion at all frequencies except 0.8 Hz, where a drop-off in coherence was observed. Mean frequency of head and body sway matched the driving frequency </=0.4 Hz. At higher frequencies, non-1:1 coupling was evident. The phase of body sway relative to the touch plate averaged 20-30 degrees at 0.1-Hz drive and decreased approximately linearly to -130 degrees at 0.8-Hz drive. System gain was approximately 1 across frequency. The large phase lags observed cannot be accounted for with velocity coupling alone but indicate that body sway also was coupled to the position of the touch plate. Fitting of a linear second-order model to the data suggests that postural control parameters are not fixed but adapt to the moving frame of reference. Moreover, coupling to both position and velocity suggest that a spatial reference frame is defined by the somatosensory system.
Light touch contact of a fingertip with a stationary surface can provide orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip provide sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, we asked to which extent somatosensory cues are part of the postural control system, that is, which sensory signal supports this coupling? We investigated postural control not only when the contact surface was stationary, but also when it was moving rhythmically (from 0.1 to 0.5 Hz). In doing so, we brought somatosensory cues from the hand into conflict with other parts of the postural control system. Our focus was the temporal relationship between body sway and the contact surface. Postural sway was highly coherent with contact surface motion. Head and body sway assumed the frequency of the moving contact surface at all test frequencies. To account for these results, a simple model was formulated by approximating the postural control system as a second-order linear dynamical system. The influence of the touch stimulus was captured as the difference between the velocity of the contact surface and the velocity of body sway, multiplied by a coupling constant. Comparison of empirical results (relative phase, coherence, and gain) with model predictions supports the hypothesis of coupling between body sway and touch cues through the velocity of the somatosensory stimulus at the fingertip. One subject, who perceived movement of the touch surface, demonstrated weaker coupling than other subjects, suggesting that cognitive mechanisms introduce flexibility into the postural control scheme.
A widely used task in the research on spoken word recognition is phoneme monitoring, in which subjects have to detect phonemes in spoken words. It is generally assumed that this task is performed using phonetic or phonological representations of words only. To test whether an orthographic representation of the words is employed as well, an experiment was conducted in which Dutch subjects monitored for phonemes with either a primary or secondary spelling in phonologically matched spoken words and nonwords. Phoneme monitoring times were slower when the phoneme had a secondary spelling than when it had a primary spelling. The effect was greater after than before the uniqueness point of the word, and monitoring times were faster for words than for nonwords. These findings indicate that an orthographic representation of words is engaged in phoneme monitoring.
Sixteen dairy cows with chronic puerperal endometritis between 3 and 8 weeks post partum were treated with intra-uterine applied oxytetracycline (OTC) and lugol. OTC was rapidly removed from plasma and was not detectable after 48 hours. The concentration of OTC in milk did not exceed 40 micrograms/kg, and it was still detectable in milk 34 hours after treatment. The concentration of OTC in milk was always lower than the limit of 50 micrograms/kg used by milk-testing stations and the European limit (MRL) of 100 micrograms/kg. Milk from cows treated with lugol did not cause inhibition in the plate test.
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A divided attention paradigm was used to investigate whether graphemes and phonemes can mutually activate or inhibit each other during bimodal processing. In 3 experiments, Dutch subjects reacted to visual and auditory targets in single-channel or bimodal stimuli. In some bimodal conditions, the visual and auditory targets were nominally identical or redundant (e.g., visual A and auditory /a/); in others they were not (e.g., visual U and auditory /a/). Temporal aspects of cross-modal activation were examined by varying the stimulus onset asynchrony of visual and auditory stimuli. Cross-modal facilitation--but not inhibition--occurred rapidly and automatically between phoneme and grapheme representations. Implications for current models of bimodal processing and word recognition are discussed.