Dark-field microscopy in the assessment of large colon microperfusion and mucosal injury in naturally occurring surgical disease of the equine large colon.

REASON FOR PERFORMING STUDY: Intraoperative assessment of colonic viability can be challenging and largely subjective. Objective methods are often impractical. Viability is related to re-establishment of colonic perfusion; particularly microvascular perfusion. This study evaluated the utility of dark-field microscopy (DFM) of the colonic serosa as an objective method of assessing microperfusion. OBJECTIVES: To measure microvascular perfusion indices (MPI) of the pelvic flexure serosa in horses with surgical colonic lesions and correlate these with macroperfusion indices (MaPI) and histomorphometry. STUDY DESIGN: Prospective, clinical, case-control study. METHODS: Control horses and horses with colonic volvulus (LCV), displacement, and/or simple obstruction undergoing surgery had DFM video loops performed on the pelvic flexure. Total vessel density, perfused vessel density, proportion of perfusion vessels and microvascular flow index were calculated from video analysis. Macroperfusion indices (arterial blood pressure and heart rate) were recorded. Histomorphometry was used to determine a mucosal injury score. Differences between lesions for MPI, MaPI and histomorphometry were compared using ANOVA or Kruskal-Wallis statistic. Spearman correlations between MPI with MaPI were performed. Linear regression was used to assess the relationship between MPI and histomorphometry. P<0.05 was significant. RESULTS: Horses with LCV had lower perfused vessel density, proportion of microvascular perfusion vessels and flow index than horses with nonstrangulating obstructions and control horses. Macroperfusion indices were not correlated with MPI but MPI were correlated with histomorphometry. CONCLUSIONS: Dark-field microscopy is achievable in the operating room and can quantify MPI from the colonic serosa in different colonic lesions. Macroperfusion indices were not related with colonic MPI. Microvascular perfusion indices can predict the severity of histopathological change at the pelvic flexure. Derangements of MPI may be more useful indicators of colonic pathology and viability and offer a more objective assessment of intestinal injury than subjective methods. Further study is needed to determine the utility of DFM in predicting survival in horses with LCV.

Thromboelastography in healthy, sick non-septic and septic neonatal foals.

OBJECTIVES: To evaluate citrated recalcified thromboelastography (TEG) in healthy newborn foals, and to determine intra-assay, inter-individual and intra-individual (at 12 h, 24 h and 7 days after birth) variations. Additionally, to compare TEG variables, haematological values and conventional coagulation profiles from healthy, sick non-septic, and septic foals. DESIGN: Prospective study. METHODS: The study group comprised 18 healthy, 15 sick non-septic and 17 septic foals. Two citrated (3.2%; 1 : 9 anticoagulant : blood ratio) blood samples were submitted for haemostatic evaluation using a TEG analyser and conventional coagulation profile. TEG values (R time (R), K time (K), angle (α), maximum amplitude (MA) and G value (G)), complete blood count (CBC) and conventional coagulation profile (prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration (Fib) and antithrombin (AT)) were evaluated. Signalment, presenting complaint, sepsis scores, blood culture results and outcome were taken from the medical records of the sick foals. RESULTS: Mean values ± SD for TEG variables in healthy neonatal foals were: R = 11.82 ± 5.35 min, K = 3.06 ± 1.34 min, α= 51.19 ± 12.66 degrees, MA = 55.06 ± 6.67 mm and G = 6361 ± 1700 dyn/cm(2) . Mean coefficients of variation for intra-assay/inter-individual/intra-individual in healthy foals were: R = 3.5/45.2/43.1%; K = 5.3/58.7/28.7%; α= 1.5/24.7/11.9%; MA = 0.3/12.1/6.1%; G = 1.6/26.7/14.7%. Septic foals had significantly greater α, MA and G values than sick non-septic foals, and significantly greater MA and G than healthy foals, changes that are consistent with hypercoagulability. Weak correlations were detected between TEG variables and haematological or haemostatic values. CONCLUSIONS: TEG could be used to provide additional information about the haemostatic system in equine neonates.

Naturally occurring compensated insulin resistance selectively alters glucose transporters in visceral and subcutaneous adipose tissues without change in AS160 activation.

Although the importance of adipose tissue (AT) glucose transport in regulating whole-body insulin sensitivity is becoming increasingly evident and insulin resistance (IR) has been widely recognized, the underlying mechanisms of IR are still not well understood. The purpose of the present study was to determine the early pathological changes in glucose transport by characterizing the alterations in glucose transporters (GLUT) in multiple visceral and subcutaneous adipose depots in a large animal model of naturally occurring compensated IR. AT biopsies were collected from horses, which were classified as insulin-sensitive (IS) or compensated IR based on the results of an insulin-modified frequently sampled intravenous glucose tolerance test. Protein expression of GLUT4 (major isoform) and GLUT12 (one of the most recently discovered isoforms) were measured by Western blotting in multiple AT depots, as well as AS160 (a potential key player in GLUT trafficking pathway). Using a biotinylated bis-mannose photolabeled technique, active cell surface GLUT content was quantified. Omental AT had the highest total GLUT content compared to other sites during the IS state. IR was associated with a significantly reduced total GLUT4 content in omental AT, without a change in content in other visceral or subcutaneous adipose sites. In addition, active cell surface GLUT-4, but not -12, was significantly lower in AT of IR compared to IS horses, without change in AS160 phosphorylation between groups. Our data suggest that GLUT4, but not GLUT12, is a pathogenic factor in AT during naturally occurring compensated IR, despite normal AS160 activation.

Insulin resistance selectively alters cell-surface glucose transporters but not their total protein expression in equine skeletal muscle.

BACKGROUND: Insulin resistance (IR) has been widely recognized in humans, and more recently in horses, but its underlying mechanisms are still not well understood. The translocation of glucose transporter 4 (GLUT4) to the cell surface is the limiting step for glucose uptake in insulin-sensitive tissues. Although the downstream signaling pathways regulating GLUT translocation are not well defined, AS160 recently has emerged as a potential key component. In addition, the role of GLUT12, one of the most recently identified insulin-sensitive GLUTs, during IR is unknown. HYPOTHESIS/OBJECTIVES: We hypothesized that cell-surface GLUT will be decreased in muscle by an AS160-dependent pathway in horses with IR. ANIMALS: Insulin-sensitive (IS) or IR mares (n = 5/group). METHODS: Muscle biopsies were performed in mares classified as IS or IR based on results of an insulin-modified frequently sampled IV glucose tolerance test. By an exofacial bis-mannose photolabeled method, we specifically quantified active cell-surface GLUT4 and GLUT12 transporters. Total GLUT4 and GLUT12 and AS160 protein expression were measured by Western blots. RESULTS: IR decreased basal cell-surface GLUT4 expression (P= .027), but not GLUT12, by an AS160-independent pathway, without affecting total GLUT4 and GLUT12 content. Cell-surface GLUT4 was not further enhanced by insulin stimulation in either group. CONCLUSIONS AND CLINICAL IMPORTANCE: IR induced defects in the skeletal muscle glucose transport pathway by decreasing active cell-surface GLUT4.

Proinflammatory cytokine and chemokine gene expression profiles in subcutaneous and visceral adipose tissue depots of insulin-resistant and insulin-sensitive light breed horses.

BACKGROUND: Insulin resistance has been associated with risk of laminitis in horses. Genes coding for proinflammatory cytokines and chemokines are expressed more in visceral adipose tissue than in subcutaneous adipose tissue of insulin-resistant (IR) humans and rodents. HYPOTHESIS/OBJECTIVES: To investigate adipose depot-specific cytokine and chemokine gene expression in horses and its relationship to insulin sensitivity (SI). ANIMALS: Eleven light breed mares. METHODS: Animals were classified as IR (SI=0.58+/-0.31x10(-4) L/min/mU; n=5) or insulin sensitive (IS; SI=2.59+/-1.21x10(-4) L/min/mU; n=6) based on results of a frequently sampled intravenous glucose tolerance test. Omental, retroperitoneal, and mesocolonic fat was collected by ventral midline celiotomy; incisional nuchal ligament and tail head adipose tissue biopsy specimens were collected concurrently. The expression of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, plasminogen activator inhibitor-1 (PAI-1), and monocyte chemoattractant protein-1 (MCP-1) in each depot was measured by real-time quantitative polymerase chain reaction. Data were analyzed by 2-way analysis of variance for repeated measures (P<.05). RESULTS: No differences in TNF-alpha, IL-1beta, IL-6, PAI-1, or MCP-1 mRNA concentrations were noted between IR and IS groups for each depot. Concentrations of mRNA coding for IL-1beta (P=.0005) and IL-6 (P=.004) were significantly higher in nuchal ligament adipose tissue than in other depots. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that the nuchal ligament depot has unique biological behavior in the horse and is more likely to adopt an inflammatory phenotype than other depots examined. Visceral fat may not contribute to the pathogenesis of obesity-related disorders in the horse as in other species.

Clinical assessment and outcome of a single-layer technique for anastomosis of the small intestine in horses.

In order to assess postoperative outcome in horses undergoing end-to-end anastomosis of the small intestine, performed using a one-layer technique, 15 horses that underwent exploratory coeliotomy, resection of the small intestine and end-to-end anastomosis using a continuous Lembert pattern were studied. Information on the age, breed, sex, diagnosis, treatment, complications and outcome of each case were obtained from medical records. Follow-up information was obtained via telephone conversations with clients and trainers. Five of the horses had short-term postoperative complications: one had postoperative ileus (POI), colic and peritonitis, one had POI and colic, two had POI only and one had diarrhoea only. A second exploratory coeliotomy was recommended in two of the 15 horses (13 per cent). The short-term survival rate, defined as survival up to the time of discharge from the hospital, was 93.3 per cent (14 of 15 horses). The long-term survival rate, defined as survival for at least 12 months after the surgery, was 84.6 per cent (11 of 13 horses followed up).

Calcium regulating hormones and serum calcium and magnesium concentrations in septic and critically ill foals and their association with survival.

BACKGROUND: Disorders of calcium regulation are frequently found in humans with critical illness, yet limited information exists in foals with similar conditions including septicemia. The purpose of this study was to determine whether disorders of calcium exist in septic foals, and to determine any association with survival. HYPOTHESIS: Blood concentrations of ionized calcium (Ca(2+)) and magnesium (Mg(2+)) will be lower in septic foals with concomitant increases in parathyroid hormone (PTH), calcitonin (CT), and parathyroid-related peptide (PTHrP) compared with healthy foals. The magnitude of these differences will be negatively associated with survival. ANIMALS: Eighty-two septic, 40 sick nonseptic, and 24 healthy foals of or=14 were considered septic. Foals with disease other than sepsis and healthy foals were used as controls. Hormone concentrations were measured with validated immunoassays. RESULTS: Septic foals had decreased Ca(2+) (5.6 versus 6.1 mg/dL, P < .01) and increased serum PTH (16.2 versus 3.2 pmol/L, P < .05), and phosphorus concentrations (7.1 versus 6.3 mg/dL, P < .01). No differences in serum Mg(2+), PTHrP, and CT concentrations were found. Nonsurviving septic foals (n = 42/82) had higher PTH concentrations (41.1 versus 10.7 pmol/L, P < .01) than survivors (n = 40/82). CONCLUSIONS AND CLINICAL IMPORTANCE: Septic foals were more likely to have disorders of calcium regulation compared with healthy foals, where hyperparathyroidemia was associated with nonsurvival.

Blood arginine vasopressin, adrenocorticotropin hormone, and cortisol concentrations at admission in septic and critically ill foals and their association with survival.

BACKGROUND: Sepsis is an important cause for neonatal foal mortality. The hypothalamic-pituitary-adrenal axis (HPAA) responses to sepsis are well documented in critically ill humans, but limited data exist in foals. The purpose of this study was to evaluate the HPAA response to sepsis in foals, and to associate these endocrine changes with survival. HYPOTHESIS: Blood concentrations of arginine vasopressin (AVP), adrenocorticotropin hormone (ACTH), and cortisol will be higher in septic foals as compared with sick nonseptic and healthy foals. The magnitude of increase in hormone concentration will be negatively associated with survival. ANIMALS: Fifty-one septic, 29 sick nonseptic, and 31 healthy foals of < or =7 days of age were included. METHODS: Blood was collected at admission for analysis. Foals with positive blood culture or sepsis score > or =14 were considered septic. Foals admitted with disease other than sepsis and healthy foals were used as controls. AVP, ACTH, and cortisol concentrations were measured using validated immunoassays. RESULTS: AVP, ACTH, and cortisol concentrations were increased in septic foals. Septic nonsurvivor foals (n = 26/51) had higher plasma ACTH and AVP concentrations than did survivors (n = 25/51). Some septic foals had normal or low cortisol concentrations despite increased ACTH, suggesting relative adrenal insufficiency. AVP, ACTH, and cortisol concentrations were higher in sick nonseptic foals compared with healthy foals. CONCLUSIONS AND CLINICAL IMPORTANCE: Increased plasma AVP and ACTH concentrations in septic foals were associated with mortality. Several septic foals had increased AVP : ACTH and ACTH : cortisol ratios, which indicates relative adenohypophyseal and adrenal insufficiency.

Overuse injuries in the elite rock climber.

UNLABELLED: Closed rupture of the flexor tendon sheath has been known to occur in the elite rock climbing population. However, only one study has investigated the prevalence of this entity. PURPOSE: To examine an elite climbing group in this country for the prevalence of pulley rupture and report on other commonly occurring injuries in the hand and elbow. METHODS: 42 elite rock climbers competing at the U.S. national championships were evaluated by an injury survey and concentrated examination of the hand and elbow. Manual testing for clinical bowstringing was done for each finger, by the same examiner. RESULTS: 11 subjects (26%) had evidence of flexor pulley rupture or attenuation, as manifested by clinical bowstringing. Injury to the PIP collateral ligament had occurred in 17 subjects (40%). Other commonly occurring injury syndromes are described. CONCLUSION: Our results and others suggest that closed traumatic pulley rupture occurs with significant frequency in this population. In addition, all subjects with this injury continued to climb at a high standard and reported no functional disability.

Radiographic osteoarthritis in the hands of rock climbers.

Sixty-five rock climbers were radiographically evaluated for osteoarthritis of the finger joints. Only long-time climbers were chosen for this study. The average years of climbing experience of these subjects was 19.8 (range, 8 to 39). The majority of the subjects had climbed at an elite level for many years. Plain radiographs of the hands were scored using the Kellgren-Lawrence scale and were compared with scores of an age-matched control group. An increased rate of osteoarthritis for several joints was found in the climber group; however, no significant difference in the overall prevalence of osteoarthritis was found between the two groups.

Hand involvement in multiple hereditary exostosis.

In summary, patients with multiple hereditary exostosis often inherit hand involvement but rarely show hand deformity. The principal area of involvement appears to be around the MCP joint but the PIP joint is the most common area of deformity. Metacarpal shortening usually does not cause functional problems and need not be treated. Angular deformity, though rare, does cause problems and needs surgical treatment. Unfortunately, there is no evidence that prevention of deformity is possible by early excision of osteochondromas. Treatment, therefore, requires both osteochondroma excision and closing-wedge corrective osteotomy.

A prospective 10-year study of the post-thrombotic syndrome in a surgical population.

A total of 564 patients undergoing laparotomy entered a prospective 10-year study to determine the influence of postoperative DVT relative to other thrombotic episodes on the subsequent development of post-thrombotic syndrome (PTS). Pre-existing venous thrombotic disease and postoperative thromboses were assessed at the initial hospitalisation. Subsequent thrombotic episodes and signs of PTS have been monitored at biennial review. Thirty-five patients had PTS by the tenth year but it was already present in 16 before the index operation. Twenty-six patients without previous thrombotic episodes developed spontaneous DVT or phlebitis during the 10-year follow-up. New leg ulcers developed in six patients. Although all thrombotic episodes, irrespective of the relation to the index operation, increased the risk of PTS, most PTS occurred in patients without recognised DVT, although most had lesser venous problems prior to operation. PTS should be seen as resulting from the summation of a number of incidents of damage to the leg veins rather than one postoperative incident. Direction of prophylactic effort to patients with pre-existing venous problems may best reduce PTS among patients undergoing abdominal surgery, but will not make a major impact on the total population incidence of PTS.

Treatment of neuromas about a major amputation stump.

In five patients, with intractable pain from neuromas that developed after amputations at the wrist or forearm, the neuromas were resected and the median nerve anastamosed to the ulnar nerve under the pronator teres muscle. In one patient, the anterior interosseous nerve was also anastamosed to the superficial radial nerve under the muscles of the forearm. Patients reported an 80% to 90% reduction in pain. This procedure is limited to patients in which all other treatments have failed.

Recurrence after surgical treatment of hidradenitis suppurativa.

From six to 89 months after surgery 82 patients who had been treated by radical surgery (118 excisions) for intractable hidradenitis suppurativa were reviewed. Local recurrence rates varied greatly with the disease site, being low after axillary (3%) and perianal surgery (0%) and high after inguinoperineal (37%) and submammary (50%) excision. Recurrence results from inadequate excision or an unusually wide distribution of apocrine glands, but physical factors such as obesity, local pressure, and skin maceration played a part in a few patients. Recurrence due to inadequate surgery tended to be the most troublesome. At follow up 75 (91%) of the patients were pleased with the results of their operation. A quarter of the patients developed disease at a new anatomical site after operation. Radical surgery gives good symptomatic control of severe hidradenitis suppurativa of the axilla, inguinoperineal, and perianal regions but is less satisfactory for submammary disease.

Incisional hernia: a 10 year prospective study of incidence and attitudes.

Five hundred and sixty-four patients reviewed 1 year after major abdominal surgery have been studied prospectively by a single observer for 10 years to determine the incidence and significance of incisional hernia. Of 337 (60 per cent) patients completing the 10 year follow-up 37 (11 per cent) developed an incisional hernia and 13 (35 per cent) of these first appeared at 5 years or later. One in three hernias caused symptoms. The late appearing hernias were smaller than the early ones, and caused little trouble. Of the 18 patients who consulted their general practitioner, 11 had symptoms and of these six (55 per cent) were referred for surgical opinion. Many hernias were diagnosed at routine outpatient follow-up and were likely to receive treatment from the surgeon. Most symptomatic patients were offered surgery with the remainder usually being offered a corset. In about half our patients (mainly those without symptoms) surgery was refused or advised against although the patients would have accepted it. Recurrence is common after surgical repair (40 per cent) but seems to be related to surgical technique. The possibility of complications occurring from an incisional hernia does not appear to be discussed with patients although obstruction occurred in 14 per cent of our patients with troublesome hernia.

Rotator cuff tears associated with os acromiale.

We studied the cases of eight patients, one with bilateral involvement, who had a rotator cuff tear and an associated lesion delineated roentgenographically - a separate fragment of the acromion that we believe to be an ununited ossification center of the acromion (os acromiale). In reviewing the literature, we found no mention of an association between a rotator cuff tear and os acromiale. It is highly unlikely that such an association is coincidental because it appears that in our patients abnormal motion existed through the site of fibrous union of the acromion and may have contributed to the impingement of the acromion on the rotator cuff. Repair of the rotator cuff with removal of the loose fragment of acromion was done in the six patients who had operative treatment.