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Biomedical subjects

N D Cohen

Publications and source records attributed to N D Cohen.

At least 55 records · Page 3Linked to original sources

Racing-related factors and results of prerace physical inspection and their association with musculoskeletal injuries incurred in thoroughbreds during races.

OBJECTIVE: To describe and compare data from Thoroughbreds that sustained musculoskeletal injuries while racing with data from matched control horses. DESIGN: Matched case-control study. ANIMALS: 216 Thoroughbreds that sustained a musculoskeletal injury while racing and 532 horses from the same races that were not injured. PROCEDURE: Data regarding racing history, race-entrant characteristics, racing events determined by analysis of videotapes of races, and results of prerace physical inspections were determined for all horses. Injured horses were compared with control horses by using conditional logistic regression. RESULTS: Results of prerace inspection by regulatory veterinarians were significantly associated with injury. Odds of musculoskeletal injury, injury of the suspensory apparatus of the forelimb, and injury of the tendon of the superficial digital flexor muscle of the forelimb were 5.5 to 13.5 times greater among horses assessed to be at increased risk of injury by regulatory veterinarians on the basis of results of prerace inspection than for horses not considered to be at increased risk of injury. Odds of an abnormal finding in the suspensory ligament during prerace inspection were 3.4 times greater among horses that injured the suspensory apparatus than among control horses, and odds of an abnormal finding in the tendon of the superficial digital flexor muscle during prerace inspection were 15 times greater among horses that injured the tendon than among control horses. CLINICAL IMPLICATIONS: Regulatory veterinarians can identify horses during prerace physical inspection that have an increased risk of injury during races. Prerace physical inspections could be used to reduce the risk of injury to Thoroughbreds during races.

Animals↗

Risk factors for wound infection following celiotomy in horses.

OBJECTIVE: To determine the prevalence of wound infection following celiotomy in horses and to determine risk factors associated with the development of such infections. DESIGN: Prospective study. ANIMALS: 210 horses that had 235 celiotomies. PROCEDURE: All horses that had celiotomies between March 1990 and March 1992 were considered for this study. Only horses that survived > or = 10 days after surgery were included in analysis of risk factors for postoperative wound infection. RESULTS: Of the 210 horses, 161 (76.7%) were discharged; of the horses discharged, 147 horses had a single celiotomy and 14 had multiple celiotomies. Twenty-six (12.4%) horses were euthanatized during surgery and were, therefore, excluded from further analysis. Twenty-three horses died during the postoperative period. Of these 23 horses, 15 that died within 10 days of surgery also were excluded from further analysis. Thus, 169 horses were included in the analysis of risk factors for developing incisional infection. Evidence of incisional infection was observed in 43 of 169 (25.4%) horses. Increased concentration of fibrinogen in peritoneal fluid obtained prior to surgery, performing an enterotomy, and use of polyglactin 910 to close the linea alba were all significantly (P < or = 0.05) associated with increased risk of postoperative wound infection. Whether incisional herniation developed was recorded for 76 horses. The proportion of horses with hernias among those with postoperative wound infection was 19.1%, compared with 3.6% of horses without evidence of postoperative wound infection, indicating a significant association between postoperative wound infection and development of incisional hernias. CLINICAL IMPLICATIONS: Increased concentration of fibrinogen in peritoneal fluid prior to surgery, performing an enterotomy, and use of polyglactin 910 to close the linea alba is significantly associated with increased risk for wound infection following celiotomy in horses.

Abdomen↗

Epidemiology of colic.

Understanding the epidemiology of equine colic is directly relevant to the management of individual horses with colic. In this article, the epidemiology of colic is reviewed with emphasis on epidemiologic studies that have identified specific factors associated with increased risk of colic and epidemiologic studies that are designed to predict the need for surgery and prognosis in horses with colic. Despite the magnitude of the problem of equine colic, much remains to be learned about the epidemiology of this disease.

Animals↗

Crohn's disease and ulcerative colitis are associated with the DNA repair gene MLH1.

OBJECTIVE: The purpose of this study was to determine whether there is an association between Crohn's disease and ulcerative colitis with MLH1. SUMMARY BACKGROUND DATA: Identification of genes involved in the etiology of inflammatory bowel disease may lead to the development of markers that objectively can define disease and permit therapy. The treatment of Crohn's disease of the colon and ulcerative colitis also is complicated by difficulties in differentiating the two conditions. METHODS: The DNA and clinical data were obtained on 126 unrelated individuals (45 Crohn's disease, 36 ulcerative colitis, and 45 control subjects without intestinal disease). Polymerase chain reaction products were analyzed by single-strand conformation polymorphisms (MLH1 exons 9, 11, 14, 15, and 16) and polyacrylamide gel electrophoresis (markers D3S1611 and D3S1768). All comparisons were analyzed by chi square test. The association between single haplotypes and disease was expressed as relative odds. RESULTS: MLH1 exons 9, 11, 14, and 16 were monomorphic. Two, four, and six alleles were detected in MLH1 exon 15, D3S1611, and D3S1768, respectively. Significant associations were observed for MLH1 exon 15/D3S1611 haplotypes AB (OR = 5.5; p = 0.007) and BA (p = 0.002) with Crohn's disease and for haplotypes AB (OR = 4.0; p = 0.042), BA (p = 0.035), and BC (OR = 6.1; p = 0.016) with ulcerative colitis. Family history of inflammatory bowel disease was associated with D3S1768/D3S1611 (p = 0.05) and MLH1 exon 15/D3S1611 haplotypes (p = 0.03). D3S1611/D3S1768 haplotype CD (OR = 11.3; p = 0.03) was associated with disease, whereas MLH1 exon 15/D3S1611 haplotype AA (OR = 0.25; p = 0.02) was protective. Comparisons of MLH1 exon 15/D3S1611 haplotypes of Crohn's colitis and patients with ulcerative colitis were significant (p = 0.037). CONCLUSIONS: This study identifies a novel genetic and clinical association between MLH1 and inflammatory bowel disease.

Adaptor Proteins, Signal Transducing↗

Bovine lymphocyte antigen class II alleles as risk factors for high somatic cell counts in milk of lactating dairy cows.

Lactating Holstein cows (n = 1100) from 93 dairy herds in Iowa, Wisconsin, Minnesota, and Illinois were genotyped at the bovine lymphocyte antigen DRB3.2 locus by a genotyping system that used polymerase chain reaction and restriction fragment length polymorphisms. Milk samples were obtained after routine processing at a Dairy Herd Improvement Association facility and returned to the National Animal Disease Center for DNA extraction. Somatic cells were used to classify cows that had acutely elevated SCC (one test of SCC > 500,000; group 1), or chronically elevated SCC (three consecutive tests of SCC > 300,000 or two consecutive tests of > 500,000; group 2), or that were eligible as controls. For each cow in groups 1 and 2, controls were selected that were matched for breed, lactation, herd, and days in lactation (+/-60 d). A conditional model for stepwise logistic regression was used to determine the relative odds for the 10 alleles with a frequency > 3%. No significant associations were observed when the 292 cows in group 2 were compared with their 292 controls. Allele *16 was associated with an increased risk of disease for cows classified with an acute SCC (258 cases and 258 controls). This study has identified DRB3.2*16 as a potential risk factor for acute intramammary infection and established the use of Dairy Herd Improvement Association milk samples as a source of DNA that is useful for genetic epidemiologic studies.

Alleles↗

Case-control study of risk factors for the development of laminitis in the contralateral limb in Equidae with unilateral lameness.

OBJECTIVE: To identify risk factors associated with development of laminitis of the supporting limb in Equidae with unilateral laminitis and to determine the radiographic appearance of this type of laminitis. DESIGN: Retrospective analysis of medical records. ANIMALS: 20 Equidae with unilateral lameness that developed laminitis of the contralateral limb. PROCEDURE: Case animals were compared with matched and unmatched populations of control animals that did not develop contralateral limb laminitis. Lateromedial radiographic projections of affected feet were evaluated for evidence of laminitis. RESULTS: Body weight of case animals was not significantly different from that of control animals, but number of days that control animals were lame prior to recovery was significantly less than number of days that case animals were lame prior to the onset of laminitis. Lateromedial radiographic projections of the foot of the support limb were available for 16 of the 20 case animals. For all 16, thickness of the soft tissue dorsal to the distal phalanx was > 29% of the palmar cortical length of the distal phalanx, but only 1 had evidence of rotation of the distal phalanx. The proportion of case animals that were euthanatized was significantly greater than the proportion of control animals that were euthanatized. CLINICAL IMPLICATIONS: Duration of lameness, but not body weight, was a risk factor for development of laminitis in the contralateral limb in Equidae with unilateral lameness, and animals that developed this complication were more likely to be euthanatized than were animals that did not.

Animals↗

Risk factors associated with development of diarrhea in horses after celiotomy for colic: 190 cases (1990-1994).

OBJECTIVE: To determine the incidence of the risk factors for developing diarrhea in horses after celiotomy for colic. DESIGN: Retrospective cohort study. ANIMALS: 357 adult horses that had celiotomy for colic at the teaching hospital between Jan 1, 1990 and Sep 1, 1994. PROCEDURE: Medical records of horses that had celiotomy for colic were reviewed to abstract information regarding development of diarrhea, signalment, history, and treatment. RESULTS: In horses that had celiotomy for colic, the incidence of diarrhea was 53.2% (190/357). Using multiple logistic regression, horses with a disorder of the large intestine were approximately twice as likely to develop diarrhea after celiotomy as horses that had surgery for other types of intestinal lesions (P < 0.001). Even after accounting for the effects of large intestinal surgery, horses that also had an enterotomy were approximately 1.5 times as likely to develop diarrhea (P = 0.042). Diarrhea in horses associated with duration > 2 days, isolation of Salmonella spp from feces, or leukopenia was categorized as being severe. Incidence of severe diarrhea was 27.5% (98/357). Using multiple logistic regression, horses that had surgery of the large intestine were approximately 2.5 times as likely to develop severe diarrhea after celiotomy as horses that had surgery for other types of intestinal lesions (P = 0.006). In horses that had celiotomy for colic, those that were fed grass hay were approximately half as likely to develop severe diarrhea as were horses that were not fed grass hay (P = 0.018). CLINICAL IMPLICATIONS: Although the risk factors identified for the development of diarrhea are not alterable, knowledge of them will enable clinicians to better advise clients and to better prepare for medical management of horses after surgery.

Animal Feed↗

Risk factors for history of previous colic and for chronic, intermittent colic in a population of horses.

OBJECTIVE: To identify risk factors for recurrent colic and chronic, intermittent colic in horses. DESIGN: Case control study. ANIMALS: The population included 768 horses examined by veterinarians for emergencies other than colic (control group). PROCEDURE: Horses with colic that had history of colic (n = 232) were compared with those without such history (n = 536), using logistic regression analysis to identify risk factors for history of previous colic and to determine odds ratios (OR) for these associations. Among the 232 horses in the history of colic group, 58 horses that had chronic, intermittent colic were compared with the no history of colic group and the control group to identify factors associated with chronic, intermittent colic, using multiple logistic regression analysis. RESULTS: Among horses with colic, factors significantly associated with history of colic by multiple logistic regression analysis included history of abdominal surgery (OR = 3.1; P < 0.0001), age > 8 years (OR = 1.5; P < 0.0001), feeding of coastal grass hay (OR = 1.34; P 0.012), Arabian bread (OR = 1.28; P = 0.044), and recent change in stabling (OR = 0.76, P = 0.024). Among horses with colic, factors significantly associated with chronic, intermittent colic were history of previous abdominal surgery (OR = 2.2; P = 0.021), age > 8 years (OR = 2.0; P < 0.0001), being a gelding (OR = 1.7 with female as the reference population; P = 0.002), feeding of coastal grass hay (OR = 1.6; P = 0.045), and farm density < 0.5 horses/acre (OR = 1.6; P = 0.003). When the CIC group was compared with the control group, significant risk factors included history of abdominal surgery (OR = 270.7; P < 0.0001), age > 8 years (OR = 2.4; P < 0.0001), recent change in diet (OR = 2.1; P = 0.005), farm density < 0.5 horses/acre (OR = 2.0; P = 0.0001); being a gelding (OR = 1.8, with female as the reference population; P = 0.002), and Arabian breed (OR = 1.6; P = 0.050). CLINICAL IMPLICATIONS: Certain findings of signalment and management factors may identify horses at increased risk of recurrent forms of colic.

Animals↗

Evaluation of pulse oximetry in anaesthetised foals using multiple combinations of transducer type and transducer attachment site.

A commercially available pulse oximeter was evaluated in anaesthetised foals to determine its accuracy for estimating arterial haemoglobin saturation (SaO2). Five different transducer/transducer attachment site (TTAS) combinations were evaluated; 1-3) a fingertip transmission transducer attached to the foal's ear, lip and tongue, 4) an adhesive transmission transducer positioned on the foal's ear and 5) a forehead reflectance transducer placed on the ventral aspect of the foal's tail-base. Eight normal, Quarter Horse foals (age 5-10 days) were studied while under general anaesthesia. Alterations in arterial carbon dioxide tension (PaCO2) were produced by changing the level of ventilation. At each level of ventilation, alterations of arterial haemoglobin saturation (SaO2) were produced by varying the inspired fraction of oxygen (FIO2). At each level of ventilation and each level of FIO2, arterial blood samples were obtained for blood gas analysis while pulse oximeter readings were recorded simultaneously for each TTAS combination. Arterial blood oxygen saturation (SaO2) was calculated from arterial blood gas values and the equine blood oxygen dissociation curve. Pulse oximeter readings from each TTAS combination were compared with SaO2 values with linear regression analyses. Bias and precision values were determined and the sensitivity and specificity of each TTAS combination for detecting desaturation (SaO2 < 90%) were determined. Linear regression analyses indicated significant (P < 0.05) linear correlation between oxygen saturation determined by pulse oximeter (SpO2) and SaO2 for each of the 5 TTAS combinations. The combinations TTAS-1, TTAS-3 and TTAS-4 tended slightly to underestimate SaO2 at high SaO2 ranges, but overestimated SaO2 at low ranges of SaO2. Combination TTAS-2 overestimated SaO2 over all ranges of SaO2. Combination TTAS-5 consistently underestimated SaO2 at all ranges of SaO2. In general, accuracy and precision of each TTAS combination decreased at lower SaO2 ranges. All TTAS combinations, except TTAS-2 and TTAS-4, had good sensitivity for detecting SaO2 less than 90%. All TTAS combinations except TTAS-5 demonstrated good specificity. We concluded that pulse oximetry appears to be a valuable method for assessing SaO2 and detecting desaturation in anaesthetised foals. Clinicians should be aware that the type of transducer used and the anatomical site to which it is attached can have marked effects on the accuracy of pulse oximetry; and that different TTAS combinations may behave differently over various ranges of SaO2.

Anesthesia↗

Comparison of polymerase chain reaction and microbiological culture for detection of salmonellae in equine feces and environmental samples.

OBJECTIVE: To compare the sensitivity of polymerase chain reaction (PCR) with microbiological culture for detecting salmonellae in equine fecal samples and equine environmental swab specimens. DESIGN: Samples and specimens were tested by PCR and microbiological culture. SAMPLE POPULATION: A fecal sample from each of 152 horses admitted consecutively to the clinic for evaluation by the outpatient service, 282 fecal samples from 110 hospitalized horses that had been submitted to the clinical microbiology laboratory, and 313 environmental swab specimens were examined. PROCEDURE: Each sample and specimen in the study was tested, using PCR and microbiological culture. Results of PCR and culture were compared. RESULTS: Significantly (P < 0.001) more fecal samples were positive by PCR than by microbiological culture. 26 of 152 (17.1%) fecal samples collected from horses admitted by the outpatient service were positive by PCR and none was positive by culture. 71 of 110 hospitalized horses were identified as positive by PCR, compared with 11 horses identified as positive by culture. All culture-positive horses were positive by PCR. Of the 11 culture-positive horses, 10 (90.9%) were identified as PCR positive after testing of the first sample submitted, compared with 7 (63.6%) by culture. All PCR-positive horses were detected after a total of 3 samples/horse were submitted, whereas as many as 5 samples/horse was required to identify all culture-positive horses. 8 of 313 environmental specimens were positive by PCR, and none was positive by culture. CONCLUSION: The PCR method reported here was more sensitive, more rapid, and required submission of fewer samples or specimens than did microbiological culture for detecting salmonellae.

Animals↗

Case-control study of the association between various management factors and development of colic in horses. Texas Equine Colic Study Group.

The association between various management factors and development of colic was studied in 821 horses treated for colic and 821 control horses treated for noncolic emergencies by practicing veterinarians in Texas between Oct 1, 1991 and Dec 31, 1992. History of previous colic and history of previous abdominal surgery were found to be significantly associated with colic. Change in stabling conditions during the 2 weeks prior to the time of examination, recent change in diet, and recent change in level of activity significantly increased the risk for development of colic. Changes in activity level, diet, and stabling conditions were identified as potentially alterable risk factors for colic. Logistic regression was used to adjust for the effects of all variables found to be significantly associated with colic by means of univariate analysis, and only history of previous colic, history of previous abdominal surgery, and history of recent change in diet remained significantly associated with colic. Results of this study indicate that a proportion of colic cases might be prevented by minimizing changes in management practices.

Animal Husbandry↗

Detection of Salmonella enteritidis in equine feces using the polymerase chain reaction and genus-specific oligonucleotide primers.

Salmonella was identified in feces from horses, using the polymerase chain reaction (PCR) and genus-specific oligonucleotide primers. Feces from healthy horses were determined to be culture negative and PCR negative for Salmonella. Fecal samples were inoculated with known numbers of colony-forming units (CFU) of S. enteritidis. The fecal samples were enriched overnight in tetrathionate broth, and then DNA was extracted and amplified by PCR using genus-specific primers. Sensitivity of the assay extended to 10 degrees CFU Salmonella enteritidis/g feces; sensitivity of microbiologic culture with enrichment extended to 10 degrees CFU Salmonella enteritidis/g feces. Feces that were not inoculated with S. enteritidis were negative by the PCR. Detection of salmonellae in feces was possible using the PCR within 24 hours from the time of submission of samples. Because samples were enriched, isolates were available for determining antibiograms and serologic grouping or typing.

Animals↗

Changes in the intestinal mucosal cell populations of German shepherd dogs fed diets containing different protein sources.

Sixteen German Shepherd Dogs from 4 litters were IgA-deficient on the basis of at least 1 of 2 serum IgA determinations, and all had small intestinal bacterial overgrowth, as documented by quantitated small intestinal bacterial culture in another study. These dogs were fed 2 diets that differed principally in their protein source (chicken vs beef, milk, and wheat). All dogs were fed each diet for 2 weeks before the study began. Next, all dogs were fed the chicken-based diet for 2 months. Then, half the dogs (group 1) were randomly assigned to continue eating the chicken-based diet, while the other half (group 2) ate a diet containing beef, milk, and wheat proteins. The small intestine was biopsied at the beginning of the study and after dogs had eaten the assigned diet for 2 and 4 months. At 2 months, group-2 dogs had more colonic mucosal mast cells, but this difference did not persist at 4 months. At the end of the study (ie, 4 months), although all dogs were clinically normal, group-2 dogs had significantly (P = 0.010) decreased numbers of jejunal villus plasma cells. However, these histologic changes were not considered clinically important. There were no significant differences in blood eosinophil counts, serum trypsin-like immunoreactivity, or cobalamin, folate, or IgA concentration. Clinical differences were not detected between the 2 groups, before or after the study. Changes were seen in serum IgM and IgG concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Causes of and farm management factors associated with disease and death in foals.

A prospective study was conducted to describe the causes of and farm management factors associated with disease and death in a population of foals in Texas. Data from 2,468 foals at 167 farms were provided by veterinarians for all 12 months during 1991. Among 2,468 foals, 116 deaths were reported (4.7%). Pneumonia was the most commonly reported cause of death, followed by septicemia. When considered as a group, musculoskeletal disorders (traumatic, infectious, or deforming problems) represented the most common cause of all reported deaths. Daily risk of death was greatest during the first 7 days of life, and decreased with age. Risk and frequency of causes of death varied by age. Crude incident morbidity during the year was 27.4% (677/2,468). Respiratory disease was the most common cause of incident disease in the study population, followed by diarrhea. Risk of disease was greatest among < or = 7 days old, and decreased with age. Crude rate of incident of diarrhea was significantly lower among farms where foals were born on pasture, compared with that at farms where foals were born in stalls. The practice of assessing passive immunity was significantly associated with decreased morbidity from septicemia and pneumonia.

Age Factors↗

Characterization of naturally developing small intestinal bacterial overgrowth in 16 German shepherd dogs.

Sixteen German Shepherd Dogs were found, via quantitative microbial culture of intestinal fluid samples, to have small intestinal bacterial overgrowth (IBO) over an 11-month period. All dogs were deficient in serum IgA. Consistent clinical signs suggestive of an alimentary tract disorder were not observed. Serum cobalamin determinations were not helpful in detecting IBO. Serum folate concentrations had variable sensitivity and specificity for detecting dogs from which we could culture > or = 1 x 10(5) bacterial/ml from intestinal fluid samples in the nonfed state. Histologic and intestinal mucosal cytologic examinations were not useful in detecting IBO. Substantial within-dog and between-dog variation was found in the numbers and species of bacteria in the intestines. The difficulty in diagnosing IBO, the variability in organisms found in individual dogs on repeated sampling, the likelihood that intestinal fluid microbial cultures failed to diagnose IBO in some dogs, and the potential of IBO to be clinically inapparent were the most important findings in this study.

Animals↗

Prevalence of, and factors associated with, musculoskeletal racing injuries of thoroughbreds.

All horses diagnosed by a commission veterinarian of the Kentucky Racing Commission as having sustained a musculoskeletal injury, defined as an obvious change in soundness immediately before, during, or after a race held between Jan 1, 1992 and May 31, 1993 were included in a study to determine the prevalence of and factors associated with racing injuries involving the musculoskeletal system of horses competing at 4 Thoroughbred racetracks in Kentucky. During the 17-month study, there were 35,484 racing starts among 7,649 horses in 3,824 official Kentucky Racing Commission races. During this period, 132 musculoskeletal racing injuries were diagnosed among 117 horses. Twenty-eight injured horses were male, 46 were geldings, and 43 were female. The prevalence of horses with racing injuries per racing start was 0.33% (117/35,484). The injuries of 51 horses were classified as catastrophic, and 66 as noncatastrophic. The prevalence of horses with catastrophic injuries per racing start was 0.14% (51/35,484). The proportion of horses with injuries of the left forelimb, sesamoid, and third metacarpal bone in the catastrophic group was significantly (P < or = 0.05) greater than those of horses in the noncatastrophic group. The proportion of horses with injuries of the superficial digital flexor tendon among those in the catastrophic group was significantly less than that of horses in the noncatastrophic group. The distance of the race was significantly shorter and the number of turns less among horses with catastrophic injuries than among horses with noncatastrophic injuries.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Prevalence and factors associated with development of laminitis in horses with duodenitis/proximal jejunitis: 33 cases (1985-1991).

Medical records of 116 horses admitted to the Texas Veterinary Medical Center between Jan 1, 1984 and Dec 31, 1991 with duodenitis/proximal jejunitis (DPJ) were reviewed. The prevalence of laminitis was 28.4% (33/116; 95% confidence interval: 20.2 to 36.6%). The prevalence of DPJ and DPJ-associated laminitis did not appear to vary significantly by year during the study period. Anamnesis, physical examination, clinicopathologic data, and initial treatment recorded at the time of admission were reviewed to determine risk factors associated with development of laminitis associated with DPJ. A trend of increasing prevalence of laminitis with increasing weight was observed. Using a multiple logistic regression model, horses weighting > or = 550 kg were approximately twice as likely to develop laminitis than horses weighting < 550 kg (P = 0.048). Horses with hemorrhagic reflux observed at the time of admission were nearly twice as likely to develop laminitis than horses without hemorrhagic reflux (P = 0.022). Treatments administered prior to admission or at our clinic did not significantly affect development of laminitis, except for administration of heparin to prevent laminitis. Of 33 horses that developed laminitis associated with DPJ, 2 had laminitis at the time of admission. These 2 horses were excluded from analysis of the effects of heparin administered as prophylaxis for laminitis; neither horse was treated with heparin. The proportion of horses that developed laminitis among horses that received heparin (0.0%; 0/12) was significantly (P = 0.018) less than that among horses that did not receive heparin (29.8%; 31/104).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗