Evaluation of fibrin sealants in cutaneous wound closure

Human fibrin sealant (HFS) and bovine fibrin sealant (BFS) were delivered as preformulated fibrinogen-thrombin mixtures that are light activated. These formulations were evaluated in the healing of incised cutaneous wounds in beagle dogs. Four groups were differentiated by sealant type and study duration with group: BFS for 10 days, HFS for 10 days, BFS for 30 days, and HFS for 30 days. Healing was evaluated by noting incidences of open wounds, laser Doppler perfusion imaging (LDPI), planimetry, breaking strength, and histopathology. In the absence of tension, both sealants tended to hold wound edges together; however, HFS tended to be better than its controls and BFS. Both sealants augmented suture closure, necessitating fewer sutures for wound closure. At 5 and 30 days BFS wounds had more perfusion than HFS wounds, indicating more inflammation. At 10 and 30 days BFS wounds had larger scar areas than their controls, while scar areas of HFS wounds were smaller than either BFS wounds or controls. Breaking strengths indicated that HFS wounds were stronger than their controls and BFS wounds. Histologically, mild to moderate chronic-active inflammation was observed in wounds receiving either sealant, and this persisted longer in BFS wounds. Overall, HFS had positive qualities, thus showing potential for functional and cosmetic wound closure.

Relationship between motor and language activation using fMRI

The authors examined laterality ratios (i.e., [L-R]/[L+R]) from functional MRI (fMRI) scans obtained in 12 healthy volunteers during unimanual left- and right-hand finger movements and during a verb generation language task. The language and right-hand motor asymmetry ratios were correlated (rho = 0.71, p = 0.005) as were the left- and right-hand ratios (rho = -0.68, p = 0.008). Subjects with greater relative left hemisphere lateralization of language exhibit greater relative unilateral hemisphere activation during right-hand movements.

Doubly vibrationally enhanced four wave mixing: the optical analog to 2D NMR

We report the development of the four wave mixing vibrational analog to 2D NMR and demonstrate its spectral selectivity, sensitivity to the interactions causing mode coupling, and ability to spectrally resolve isotopic mixtures. The method discriminates against uncoupled vibrational modes and isolates the features that are associated with intra- or intermolecular interactions.

Role of rpoS in acid resistance and fecal shedding of Escherichia coli O157:H7

Acid resistance (AR) is important to survival of Escherichia coli O157:H7 in acidic foods and may play a role during passage through the bovine host. In this study, we examined the role in AR of the rpoS-encoded global stress response regulator sigma(S) and its effect on shedding of E. coli O157:H7 in mice and calves. When assayed for each of the three AR systems identified in E. coli, an rpoS mutant (rpoS::pRR10) of E. coli O157:H7 lacked the glucose-repressed system and possessed reduced levels of both the arginine- and glutamate-dependent AR systems. After administration of the rpoS mutant and the wild-type strain (ATCC 43895) to ICR mice at doses ranging from 10(1) to 10(4) CFU, we found the wild-type strain in feces of mice given lower doses (10(2) versus 10(3) CFU) and at a greater frequency (80% versus 13%) than the mutant strain. The reduction in passage of the rpoS mutant was due to decreased AR, as administration of the mutant in 0.05 M phosphate buffer facilitated passage and increased the frequency of recovery in feces from 27 to 67% at a dose of 10(4) CFU. Enumeration of E. coli O157:H7 in feces from calves inoculated with an equal mixture of the wild-type strain and the rpoS mutant demonstrated shedding of the mutant to be 10- to 100-fold lower than wild-type numbers. This difference in shedding between the wild-type strain and the rpoS mutant was statistically significant (P </= 0.05). Thus, sigma(S) appears to play a role in E. coli O157:H7 passage in mice and shedding from calves, possibly by inducing expression of the glucose-repressed RpoS-dependent AR determinant and thus increasing resistance to gastrointestinal stress. These findings may provide clues for future efforts aimed at reducing or eliminating this pathogen from cattle herds.

Quality controls for bovine viral diarrhea virus-free IVF embryos

Introduction of bovine viral diarrhea virus (BVDV) with cumulus-oocyte-complexes (COCs) from the abattoir is a concern in the production of bovine embryos in vitro. Further, International Embryo Transfer Society (IETS) guidelines for washing and trypsin treatment of in-vivo-derived bovine embryos ensure freedom from a variety of pathogens, but these procedures appear to be less effective when applied to IVF embryos. In this study, COCs were exposed to virus prior to IVM, IVF and IVC. Then, virus isolations from cumulus cells and washed or trypsin-treated nonfertile and degenerated ova were evaluated as quality controls for IVF embryo production. The effect of BVDV on rates of cleavage and development was also examined. All media were analyzed prior to the study for anti-BVDV antibody. Two approximately equal groups of COCs from abattoir-origin ovaries were washed and incubated for 1 h in minimum essential medium (MEM) with 10% equine serum. One group was incubated in 10(7) cell culture infective doses (50% endpoint) of BVDV for 1 h, while the other was incubated without virus. Subsequently, the groups were processed separately with cumulus cells, which were present throughout IVM, IVF and IVC. Cleavage was evaluated at 4 d and development to morulae and blastocysts at 7 d of IVC. After IVC, groups of nonfertile and degenerated ova or morulae and blastocysts were washed or trypsin-treated, sonicated and assayed for virus. Cumulus cells collected at 4 and 7 d were also assayed for virus. Anti-BVDV antibody was found in serum used in IVM and IVC but not in other media. A total of 1,656 unexposed COCs was used to produce 1,284 cleaved embryos (78%), 960 embryos > or = 5 cells (58%), and 194 morulae and blastocysts (12%). A total of 1,820 virus-exposed COCs was used to produce 1,350 cleaved embryos (74%), 987 embryos > or = 5 cells (54%), and 161 morulae and blastocysts (9%). Rates of cleavage (P = 0.021), cleavage to > or = 5 cells (P = 0.026) and development to morula and blastocyst (P = 0.005) were lower in the virus-exposed group (Chi-square test for heterogeneity). No virus was isolated from any samples from the unexposed group. For the exposed group, virus was always isolated from 4- and 7-d cumulus cells, from all washed nonfertile and degenerated ova (n = 40) and morulae and blastocysts (n = 57) and from all trypsin-treated nonfertile and degenerated ova (n = 80) and morulae and blastocysts (n = 91). Thus, virus persisted in the system despite the presence of neutralizing antibody in IVM and IVC media, and both washing and trypsin treatment were ineffective for removal of the virus. Presence of virus in 4- and 7-d cumulus cells as well as in nonfertile and degenerated ova were good indicators of virus being associated with morulae and blastocysts.

Functional MRI cerebral activation and deactivation during finger movement

OBJECTIVE

To examine interhemispheric interactions of motor processes by using functional MRI (fMRI).

BACKGROUND

Despite evidence of interhemispheric inhibition from animal, clinical, and transcranial magnetic stimulation (TMS) studies, fMRI has not been used to explore activation and deactivation during unilateral motor tasks. fMRI changes associated with motor activity have traditionally been described by comparing cerebral activation during motor tasks relative to a "resting state." In addition to this standard comparison, we examined fMRI changes in the resting state relative to a motor task.

METHODS

Thirteen healthy volunteers performed self-paced sequential finger/thumb tapping for each hand. During fMRI data acquisition, four epochs were obtained; each comprised of 30 seconds of rest, 30 seconds of right hand activity, and 30 seconds of left hand activity. Resultant echoplanar images were spatially normalized and spatially and temporally smoothed.

RESULTS

As expected, hand movements produced activation in the contralateral sensorimotor cortex and adjacent subcortical regions and, when present, the ipsilateral cerebellum. However, hand movement also produced a significant deactivation (i.e., decreased blood flow) in the ipsilateral sensorimotor cortex and subcortical regions, and when present, the contralateral cerebellum. Conjunction analysis demonstrated regions that are activated by one hand and deactivated by the contralateral hand.

CONCLUSION

Unilateral hand movements are associated with contralateral cerebral activation and ipsilateral cerebral deactivation, which we hypothesize result from transcallosal inhibition.

Effects of overexpression of growth hormone-releasing hormone on the hypothalamo-pituitary-gonadal function in the mouse

In this investigation, the neuroendocrine alterations induced by high, chronic circulating levels of endogenous growth hormone (GH) were studied in transgenic mice with ectopic overexpression of the human growth hormone-releasing hormone (h-GH-RH) gene. In comparison with their normal littermates, transgenic h-GH-RH mice had elevated plasma levels of GH, prolactin (PRL), and corticosterone. In addition, they had elevated body, liver, kidney, spleen, and pituitary weights compared with normal mice. Testis and seminal vesicle weights were also increased in transgenic mice. Although basal plasma luteinizing hormone (LH) levels, plasma estradiol levels in females, and plasma testosterone levels in males did not differ significantly between normal and transgenic animals, the LH response to castration was severely impaired in transgenic mice of both sexes. Among the biogenic amines studied in the hypothalamus, only dopamine concentrations were significantly lower in transgenic animals compared with their normal littermates. This decrease in hypothalamic dopamine may be related to the hyperprolactinemia in transgenic animals. In vitro, pituitaries from transgenic mice released significantly higher amounts of GH, and although the basal release of LH was not different in both normal and transgenic mice, the response to gonadotropin-releasing hormone was significantly smaller in transgenic mice. Cultured anterior pituitary cells from transgenic mice secreted high quantities of GH and PRL in vitro, but these quantities significantly decreased from 1 to 8 wk in culture. These results show that high, persistent levels of circulating endogenous GH induce alterations in neuroendocrine functions related to the hypothalamo-pituitary-gonadal and the hypothalamo-pituitary-adrenal axes.

The prevalence of Aeromonas species in feces of horses with diarrhea

Feces collected from 40 horses with diarrhea and 34 horses without diarrhea were examined to determine if an association existed between isolation of Aeromonas spp. and diarrhea. Samples were also examined for Salmonella spp., and identification of viruses and parasite ova. Neither Salmonella spp. nor Aeromonas spp. were isolated from the feces of 34 control horses. Aeromonas spp. were isolated from feces of 22 of 40 (55%) horses with diarrhea. Salmonella spp. were isolated from feces of 8 (20%) horses, and of these, 5 (12.5%) were also positive for Aeromonas spp. Twenty-nine isolates of Aeromonas spp. were recovered from the feces of 22 diarrheic horses. Of these isolates, more than 80% were susceptible on in vitro testing to amikacin, ceftiofur, chloramphenicol, and gentamicin. All isolates were susceptible to enrofloxacin. Diarrheic horses positive for Aeromonas were significantly (P = .04) older than diarrheic horses negative for Aeromonas spp. A significantly greater number of fecal samples were positive for Aeromonas spp. during March through August than samples examined in other months (P = .014). Results of this study indicate that Aeromonas spp. should be considered as a cause of diarrhea in horses.

Transgenic mice overexpressing the growth-hormone-releasing hormone gene have high concentrations of tachykinins in the anterior pituitary gland

According to recent reports, substance P (SP) is localized in the anterior pituitary gland within subsets of thyrotropes and somatotropes, although earlier electron-microscopic studies described the presence of this tachykinin in mammotropes and gonadotropes. Transgenic mice overexpressing the growth-hormone-releasing hormone (GHRH) gene have markedly enlarged pituitary glands, due to hyperstimulation of the somatotropes. Therefore, we speculated that if somatotropes are able to synthesize tachykinins, these peptides should be greatly increased in the anterior pituitary of transgenic GHRH mice. We found that, in accordance with our working hypothesis, both SP and neurokinin A (NKA) were markedly increased in the anterior pituitary gland of male and female transgenic mice, compared with their respective normal controls. In male transgenic mice, NKA was 13.6- and SP 20.2-fold higher than in the anterior pituitary from normal mice. In female transgenic mice, NKA was 40- and SP 100-fold higher than in the anterior pituitary from normal female mice. In male transgenic mice, NKA and neuropeptide K (NPK) contents in the anterior pituitary showed no significant changes between 26 and 50 days of age but significantly increased between 50 days and 5 months of age. The concentration of NKA in the anterior pituitary did not show significant differences between 26 days and 5 months of age, but NPK concentrations in the anterior pituitary significantly decreased with age. In female transgenic mice, NKA content and concentration in the anterior pituitary increased after 35 days of age, but NPK concentrations significantly decreased after 26 days of age. Triiodothyronine markedly decreased anterior pituitary tachykinins, but ovariectomy and estrogen administration failed to significantly affect tachykinin concentrations in the anterior pituitary of transgenic mice. Tachykinin immunostaining was detected in some somatotropes, but tachykinins were also present in cells that were not GH positive. These findings indicate that hyperstimulated somatotropes contain increased stores of tachykinins and that these cells are a source of tachykinins in the anterior pituitary. Tachykinin stores in the anterior pituitary of transgenic mice were affected by thyroid hormones but seem to be insensitive to estrogens. The GHRH transgenic mice may be an interesting model to study the regulation of tachykinin stores in the anterior pituitary gland.

The prevalence of Aeromonas species in feces of horses with diarrhea

Feces collected from 40 horses with diarrhea and 34 horses without diarrhea were examined to determine if an association existed between isolation of Aeromonas spp. and diarrhea. Samples were also examined for Salmonella spp., and identification of viruses and parasite ova. Neither Salmonella spp. nor Aeromonas spp. were isolated from the feces of 34 control horses. Aeromonas spp. were isolated from feces of 22 of 40 (55%) horses with diarrhea. Salmonella spp. were isolated from feces of 8 (20%) horses, and of these, 5 (12.5%) were also positive for Aeromonas spp. Twenty-nine isolates of Aeromonas spp. were recovered from the feces of 22 diarrheic horses. Of these isolates, more than 80% were susceptible on in vitro testing to amikacin, ceftiofur, chloramphenicol, and gentamicin. All isolates were susceptible to enrofloxacin. Diarrheic horses positive for Aeromonas were significantly (P = .04) older than diarrheic horses negative for Aeromonas spp. A significantly greater number of fecal samples were positive for Aeromonas spp. during March through August than samples examined in other months (P = .014). Results of this study indicate that Aeromonas spp. should be considered as a cause of diarrhea in horses.

How young children spend their time: television and other activities

Time-use diaries were collected over a 3-year period for 2 cohorts of 2- and 4-year-old children. TV viewing declined with age. Time spent in reading and educational activities increased with age on weekdays but declined on weekends. Time-use patterns were sex-stereotyped, and sex differences increased with age. As individuals' time in educational activities, social interaction, and video games increased, their time watching entertainment TV declined, but time spent playing covaried positively with entertainment TV. Educational TV viewing was not related to time spent in non-TV activities. Maternal education and home environment quality predicted frequent viewing of educational TV programs and infrequent viewing of entertainment TV. The results do not support a simple displacement hypothesis; the relations of TV viewing to other activities depend on the program content, the nature of the competing activity, and the environmental context.

Developmental psychopathology and the reciprocal patterning of behavior and environment: distinctive situational and behavioral signatures of internalizing, externalizing, and mixed-syndrome children

In contrast to assessment approaches that conceptualize traits as generalized response tendencies, this research develops a conditional approach that conceptualizes traits as patterns of relations between contexts and behaviors. Using extensive observations of social interactions, this study investigated internalizing, externalizing, and mixed-syndrome children identified by T. M. Achenbach's (1993) measures. Children in these groups differed in the patterning of their responses to social contexts and in the likelihood of encountering them. Mixed-syndrome children showed a distinctive behavior pattern consisting of aggressive and withdrawn responses to nonaversive contexts. The results demonstrate how measures of overall tendencies confound person and environment influences and obscure differences between children that are revealed by contextualized measures. The need to incorporate contexts more fully into clinical assessment is discussed.

Nonpharmacologic management strategies

Nonpharmacologic management strategies for Parkinson's disease should focus on educating the patient and family, empowering them to take control over the disease through physical, occupational and speech therapy, exercise, and good nutrition. An educated understanding of psycho-social resources will enable the patient and family to develop strategies to cope with life style changes encountered in the successful management of Parkinson's disease.

Developmental psychopathology and the reciprocal patterning of behavior and environment: distinctive situational and behavioral signatures of internalizing, externalizing, and mixed-syndrome children

In contrast to assessment approaches that conceptualize traits as generalized response tendencies, this research develops a conditional approach that conceptualizes traits as patterns of relations between contexts and behaviors. Using extensive observations of social interactions, this study investigated internalizing, externalizing, and mixed-syndrome children identified by T. M. Achenbach's (1993) measures. Children in these groups differed in the patterning of their responses to social contexts and in the likelihood of encountering them. Mixed-syndrome children showed a distinctive behavior pattern consisting of aggressive and withdrawn responses to nonaversive contexts. The results demonstrate how measures of overall tendencies confound person and environment influences and obscure differences between children that are revealed by contextualized measures. The need to incorporate contexts more fully into clinical assessment is discussed.

Surgical reduction of ileal impactions in the horse: 28 cases

OBJECTIVE

To evaluate the seasonal influence, signalment, type of hay consumed, clinical examination findings, and outcome after surgery for horses with ileal impaction.

STUDY DESIGN

A retrospective study.

RESULTS

Between 1988 and 1993, 28 horses had surgical correction of ileal impaction. There was a significantly higher rate of ileal impaction during the Fall (September-November, P = .0041 ). Mean duration of clinical signs of abdominal pain before referral was 15 hours. Transrectal palpation was used to localize the impaction in 11 horses. The ileal impaction was reduced by extraluminal massage aided by admixing of intestinal fluid oral to the impaction or injection of fluids intraluminally and then movement of the ingesta into the cecum alone in 24 horses. A total of 26 horses recovered from surgery; 24 horses were discharged from the hospital and eventually returned to previous use. Two horses had fatal postoperative complications: jejunocecostomy dehiscence and development of extensive small intestine adhesions after manual reduction of the impaction. One horse initially treated by manual reduction required jejunocecostomy twice for management of recurrent ileal impaction. Follow-up information was obtained for 21 horses, of which 20 were alive 1 year or longer after surgery. A total of 27 of 28 horses were fed Coastal Bermudagrass hay as the primary type of hay consumed. A total of 9 horses continued to be fed Coastal Bermudagrass hay as the only roughage source, whereas 6 horses were fed Coastal Bermudagrass with at least 50% other hay, and in 6 horses, Coastal Bermudagrass hay was entirely eliminated from the diet.

CONCLUSION AND CLINICAL RELEVANCE

Ileal impactions can be successfully reduced by celiotomy and extraluminal massage and injection techniques to soften the ingesta for passage into the cecum without enterotomy or bypass techniques in most horses. Changes in weather and feeding practices in the Fall may account for an increased risk of ileal impaction in horses in the southeastern United States at that time of year.

Gains in life expectancy from medical interventions--standardizing data on outcomes

BACKGROUND

The gain in life expectancy is an important measure of the effectiveness of medical interventions, but its interpretation requires that it be placed in context. The interpretation of gains in life expectancy is particularly problematic for preventive interventions, for which the gains are often just weeks or even days when averaged across the entire target population.

METHODS

We tabulated the gains in life expectancy from a variety of medical interventions as reported in 83 published sources and categorized them according to target population and disease. We considered prevention in populations at average risk for particular diseases, prevention in populations at elevated risk, and treatments in populations with established disease.

RESULTS

The gains in life expectancy from preventive interventions in populations at average risk ranged from less than one month to slightly more than one year per person receiving the intervention, but the gains were as high as five years or more if the prevention was targeted at persons at especially high risk. The gains in life expectancy from treatments of established disease ranged from several months (for coronary thrombolysis and revascularization to treat heart disease) to as long as nine years (for chemotherapy to treat advanced testicular cancer).

CONCLUSIONS

A gain in life expectancy from a medical intervention can be categorized as large or small by comparing it with gains from other interventions aimed at the same target population. A gain in life expectancy of a month from a preventive intervention targeted at populations at average risk and a gain of a year from a preventive intervention targeted at populations at elevated risk can both be considered large. The framework we developed for standardizing gains in life expectancy can be used in the interpretation of data on the outcomes of interventions.

Evaluation of the effects of omega-3 fatty acid-containing diets on the inflammatory stage of wound healing in dogs

OBJECTIVES

To ascertain the effects of dietary omega-3 (n-3) fatty acids on biochemical and histopathologic components of the inflammatory stage of wound healing.

ANIMALS

30 purpose-bred Beagles.

PROCEDURE

Dogs were allotted to 5 groups of 6. Each group was fed a unique dietary fatty acid ratio of omega-6 to n-3--diet A, 5.3:1; diet B, 10.4:1; diet C, 24.1:1; diet D, 51.6:1; and diet E, 95.8:1. Dogs were fed once daily for 12 weeks, then biopsy specimens were taken from 4-day-old wounds of each dog and analyzed by gas chromatography-mass spectrometry for: prostaglandin E2 (PGE2) metabolites, and ratios of omega-6 to n-3 fatty acids, arachidonic acid (AA) to eicosapentaenoic acid (EPA), adrenic acid to docosahexaenoic acid, and PGE2 to prostaglandin E3 (PGE3) metabolites.

RESULTS

Qualitative analysis was carried out on AA, EPA, adrenic acid, docosahexaenoic acid, and the major metabolite from the PGE2 and PGE3 pathway. These molecules were further quantified with respect to diet to determine significant differences. By analysis of the AA-to-EPA ratio, diet A was different from diets D and E and diets B and C were different from diet E (P < 0.05). By analysis of the PGE2-to-PGE3 metabolite ratio, diet A was different from diet E (P < 0.05). Though biochemical analysis indicated dietary dependence, histopathologic data indicated no significant difference with respect to diet groups.

CONCLUSION

The biochemical component of the inflammatory stage of wound healing can be manipulated by diet.

CLINICAL RELEVANCE

Omega-3 fatty acid-enriched diets can be used to control inflammation associated with dermatologic conditions.

Assessment of current techniques for determining tracheal luminal stenosis in dogs

OBJECTIVE

To assess the accuracy of current antemortem and postmortem techniques for determining tracheal luminal stenosis.

ANIMALS

15 dogs.

PROCEDURE

Percentage of tracheal luminal stenosis (PTLS) was determined by 6 methods, using measurements obtained by radiography, tracheoscopy, and necropsy after selected tracheostomy techniques were performed. To calculate PTLS, dorsoventral tracheal diameter was measured from preoperative and postoperative lateral cervical radiographic views. Preoperative or normal tracheal segments adjacent to the stenotic area were used to obtain normal tracheal diameter measurements. Planimetrically determined cross-sectional area (CSA), obtained from pre- and postoperative tracheoscopic photographs, was used to calculate PTLS. The CSA of tracheal specimens obtained at necropsy was determined, using the formula for an ellipse. Percentage of luminal stenosis was calculated, using CSA of the stenotic site and of segments craniad and caudad to the site obtained at necropsy or at surgery. All methods were compared with the control method of planimetrically determined CSA of sections obtained at necropsy of the tracheostomy and segments craniad and caudad to the site.

RESULTS

Correlation was poor for radiographic and tracheoscopic techniques (r = 0.146 to 0.458, P > 0.05) The formula for an ellipse accurately predicted PTLS when measurements obtained at surgery (r = 0.516, P = 0.049) or segments craniad and caudad (r = 0.853, P < 0.001) to the site were used.

CONCLUSION

Antemortem methods of assessing PTLS did not correlate with control planimetric methods. Methods using CSA determined by tracheal diameter were weakly correlated to control planimetric techniques.

CLINICAL RELEVANCE

Accurate measurement of the degree of tracheal stenosis cannot be made in clinical patients using current techniques.

Are methods for estimating QALYs in cost-effectiveness analyses improving?

OBJECTIVES

The objectives of this study were to examine variations in the methods used by researchers to estimate QALYs in published cost-effectiveness analyses, and to investigate whether the methods have improved over time.

DATA AND METHODS

Using a MEDLINE search, the authors identified 86 original cost-effectiveness analyses, published between 1975 and 1995, that used QALYs as the measure of effectiveness. For each study, they recorded the health-state classification system, the source of the preference weights, the measurement technique, and the discount rate. The methods used were compared with the recommendations of the U.S. Panel on Cost-Effectiveness in Health and Medicine.

RESULTS

Only 20% of the studies used "generic" health-state classification systems (e.g., health utilities index); 21% relied on community-based weights; 40% used formal measurement techniques (e.g., time-tradeoff method); and 88% discounted both future costs and QALYs. There was little evidence that methods had improved over time.

CONCLUSIONS

The results illustrate extensive variation in the construction of QALYs in cost-effectiveness analyses and reveal that most studies have not adhered to practices now recommended by leaders in the field. There is a need for more methodologic rigor and consistency if the results of such studies are to be compared and used for purposes of allocating resources.

Osteonecrosis after contact neodymium:yttrium aluminum garnet arthroscopic laser meniscectomy

OBJECTIVE

The purpose of this report is to describe two cases of osteonecrosis that occurred after arthroscopic meniscectomy with a contact neodymium:yttrium aluminum garnet laser system. The patients developed increasing knee pain and disability 5 months and 6 months after laser meniscectomy. MR imaging showed subchondral osteonecrosis in the femoral condyle and tibial plateau immediately adjacent to the site of laser meniscectomy in both patients. One patient required a total knee replacement to alleviate knee symptoms, and the other patient required a tibial osteotomy and surgical elevation of collapsed tibial articular surface.

CONCLUSION

To our knowledge, this complication of laser arthroscopic meniscectomy has not been reported in the radiology literature. The clinical and MR imaging features of this important complication are described and possible causative mechanisms are discussed.

Seroprevalence of Borrelia burgdorferi in dogs in Alabama, USA

A random sample of private small-animal practices in Alabama submitted sera from dogs with known tick contact. A total of 579 samples from the three geographic regions of the state were collected (58% of the targeted sample size). Sera were screened for antibodies to Borrelia burgdorferi using an indirect fluorescent antibody (IFA) test which had a sensitivity and specificity of greater than 90%. Anti-B burgdorferi titers of > or = 1:64 were considered to be positive, based on results from B. burgdorferi-inoculated dogs. Ten of the 579 samples (1.7%) were positive, and titers ranged from 1:64 to 1:512. Seropositive dogs were found throughbout the state, and there was no significant difference in seroprevalence by region (Mantel-Haenszel chi 2, P = 0.85). These results indicate that the seroprevalence for canine Lyme disease in Alabama is low and that use of the canine Lyme disease vaccine is not justified.

Profile of electrodiagnostic abnormalities in cats with GM1 gangliosidosis

OBJECTIVE

To determine which electrodiagnostic tests yield abnormal findings in cats with GM1 gangliosidosis, and to determine the approximate age of onset of electrodiagnostic abnormalities.

ANIMALS

Cats (28 to 335 days old) affected with GM1 gangliosidosis (n = 11) and unaffected controls (n = 14).

PROCEDURE

Cats were grouped by age: group 1, < or = 90 days, group 2, 91 to 200 days; and group 3, > 200 days. Electrodiagnostic tests were conducted, including needle electromyography, motor and sensory nerve conduction velocity, spinal evoked potentials, and brainstem auditory evoked potentials. Results for control and affected cats were compared, using the general linear model for ANOVA and Scheffé's test for multiple comparisons.

RESULTS

Needle electromyography did not reveal abnormal spontaneous activity in skeletal muscles of any cat; furthermore, statistical analysis did not indicate significant difference between affected and control groups for nerve conduction velocity, confirming that degeneration of peripheral nerve fibers is not a feature of this disease. However, spinal evoked potentials were abnormal in group-3 cats; conduction velocity within sensory pathways in the cranial part of the spinal cord was significantly slower in GM1-affected cats (P = 0.0002). Brainstem auditory evoked responses also were abnormal: wave V (generated in the region of the pons) had prolonged latency in cats of groups 2 and 3 (P = 0.0003 and 0.0001, respectively, at 90 decibels sound pressure level). In the oldest cats, latencies for earlier waves within the auditory pathway also were prolonged; wave I (generated by the cochlear nerve) was prolonged in group-3 cats (P = 0.0423).

CONCLUSIONS

Motor and sensory nerve conduction velocities remained within normal limits in GM1-affected cats. However, spinal evoked potentials indicated slowing in conduction velocity along the cranial part of the spinal cord in group 3 cats. Brainstem auditory evoked responses indicated prolonged latencies in cats of groups 2 and 3.

Color flow Doppler imaging and Doppler spectral analysis of the brain of neonatal dogs

Doppler ultrasonography was performed on the cerebral arteries of 19 neonatal dogs. Vascular structures were identified using anatomic preparations of brains pre-injected with a radiopaque silicone rubber product and cleared using a modified tissue clearing technique. Brain sections were subsequently radiographed or examined under a stereomicroscope. Color flow Doppler imaging was used to facilitate positioning of the Doppler calipers for measurement of peak systolic velocity, minimum diastolic velocity, and resistance index. Blood flow velocities in the internal carotid and middle cerebral arteries were lower when measured in transverse images than in sagittal images. The rostral cerebral arteries could be measured using either plane but values obtained from different locations or using different methods of measurement were statistically different. Blood flow velocities generally increased during the first month after birth. Arterial signals were diphasic with flow throughout diastole. Resistance indices most often were between 0.6 and 0.7 and did not exceed 0.86.

In vitro fertilization and in vitro culture of bovine embryos in the presence of noncytopathic bovine viral diarrhea virus

In vitro embryo production has been used extensively in research and is now offered as a commercial service, yet the hazards of introducing specific infectious agents into in vitro embryo production systems have not been completely defined. The introduction of noncytopathic bovine viral diarrhea virus (BVDV) is a special concern. One objective of this study was to determine if noncytopathic BVDV-infected uterine tubal cells in IVF and IVC systems affected the rate of cleavage and development. An additional objective was to determine if either degenerated ova or embryos produced in the presence of the infected cells had virus associated with them after washing. Follicular oocytes (n = 645) collected from slaughterhouse ovaries were matured and fertilized in vitro, and presumptive zygotes were cultured for 7 d. Primary cultures of uterine tubal cells for use during IVF and IVC were divided into 2 groups. One-half of the cultures was infected with noncytopathic BVDV while the other half was not exposed to the virus. Approximately equal groups of mature oocytes were inseminated, and the presumptive zygotes were cultured with infected or noninfected uterine tubal cells. After 7 d in IVC, zona pellucida-intact (ZP-I) morulae and blastocysts and degenerated ova were washed and assayed for the presence of infectious virus. Infections of uterine tubal cells were not apparent and did not reduce rates of cleavage and development (P > 0.05; Chi-square test for heterogeneity). After washing, BVDV was isolated at a significantly higher rate from groups of virus-exposed degenerated ova (79%) than from individual virus-exposed morulae and blastocysts (37%; P = 0.0002; Mantel-Haenszel summary, Chi-square).

Prevalence of positive Osler's manoeuver in 3387 persons screened for the Systolic Hypertension in the Elderly Program (SHEP)

The purpose of this study was to examine the prevalence of a positive Osler's manoeuver (OM) among persons screened for the Systolic Hypertension in the Elderly Program (SHEP). Information obtained from all individuals included age, gender, and race; history of antihypertensive, anticoagulant, insulin, or cardiac pacemaker use; and history of heart attack, coronary bypass surgery, or stroke. Among the persons aged 60 and over that were screened for eligibility at the Louisville SHEP Center, OM was performed on 3387 subjects. Of these, 7.2% (243 of 3387) were determined to be Osler maneuver positive (O+). O+ was more prevalent among males than among females (P = 0.025). A higher prevalence of O+ was associated with both higher age (P < 0.001) and higher blood pressure (P < 0.001). There were significantly more Osler positives among those who responded positively to 'Have you had a stroke?' (P = 0.007) and 'Are you taking anticoagulants' (P = 0.044) than among those who responded negatively to these questions. O+ was also less prevalent among those that were normotensive at the time of the screening (P = 0.046). The results of this study, when taken with those of previous studies of OM, support the cautious use of OM as a screening tool for pseudohypertension in the elderly population and as an adjunct in determining the cardiovascular risk profile of individual patients. However, further study of OM is required before it can be recommended for routine use in the assessment of hypertension among the elderly.