Surgery for chronic idiopathic constipation: pediatric and adult patients - a systematic review

BACKGROUND

Chronic idiopathic constipation (CIC) is a substantial problem in pediatric and adult patients with similar symptoms and workup; however, surgical management of these populations differs. We systematically reviewed the trends and outcomes in the surgical management of CIC in pediatric and adult populations.

METHODS

A literature search was performed using Ovid MEDLINE, Embase, Scopus, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov between January 1, 1995 and June 26, 2020. Clinical trials and retrospective and prospective studies of patients of any age with a diagnosis of CIC with data of at least 1 outcome of interest were selected. The interventions included surgical resection for constipation or antegrade continence enema (ACE) procedures. The outcome measures included bowel movement frequency, abdominal pain, laxative use, satisfaction, complications, and reinterventions.

RESULTS

Adult patients were most likely to undergo resection (94%), whereas pediatric patients were more likely to undergo ACE procedures (96%) as their primary surgery. Both ACE procedures and resections were noted to improve symptoms of CIC; however, ACE procedures were associated with higher complication and reintervention rates.

CONCLUSION

Surgical management of CIC in pediatric and adult patients differs with pediatric patients receiving ACE procedures and adults undergoing resections. The evaluation of resections and long-term ACE data in pediatric patients should be performed to inform patients and physicians whether an ACE is an appropriate procedure despite high complication and reintervention rates or whether resections should be considered as an initial approach for CIC.

A Qualitative Exploration of Stakeholders' Preferences for Early-Stage Rectal Cancer Treatment

As treatment options for patients with rectal cancer evolve, patients with early-stage rectal cancer may have a treatment choice between surgery and a trial of nonoperative management. Patients must consider the treatments' clinical tradeoffs alongside their personal goals and preferences. Shared decision-making (SDM) between patients and clinicians can improve decision quality when patients are faced with preference-sensitive care options. We interviewed 28 stakeholders (13 clinicians and 15 patients) to understand their perspectives on early-stage rectal cancer treatment decision-making. Clinicians included surgeons, medical oncologists, and radiation oncologists who treat rectal cancer. Adult patients included those diagnosed with early-stage rectal cancer in the past 5 years, recruited from an institutional database. A semi-structured interview guide was developed based on a well-established decision support framework and reviewed by the research team and stakeholders. Interviews were conducted between January 2022 and January 2023. Transcripts were coded by 2 raters and analyzed using thematic analysis. Both clinicians and patients recognized the importance of SDM to support high-quality decisions about the treatment of early-stage rectal cancer. Barriers to SDM included variable clinician motivation due to lack of training or perception of patients' desires or abilities to engage, as well as time-constrained encounters. A decision aid could help facilitate SDM for early-stage rectal cancer by providing standardized, evidence-based information about treatment options that align with clinicians' and patients' decision needs.

Perineal hernia as a sequela of anal reconstruction surgeries in perianal Crohn's disease

Perineal hernia is a rare complication of pelvic surgeries that can occur in patients with perianal Crohn's disease (pCD) as a long-term outcome of surgeries for complex fistula treatment. We present a case of a symptomatic pCD male patient with multiple perianal surgeries who presents with anal pain, diarrhea, and discharge. Magnetic resonance imaging showed a perineal hernia in the ischioanal fossa violating the convergence of the left external sphincter complex. The hernia was treated with an open primary hernia repair via the perineal approach. It recurred after 3 months, and the patient underwent secondary hernia repair with gracilis muscle interposition and mesh placement. Unfortunately, this was complicated by superficial skin dehiscence and mesh extrusion, but the flap remained viable and the hernia repair was intact. Incidence, symptoms, risk factors, imaging findings, and management of perineal hernias are reviewed.

Gender and Racial Diversity Among Colon and Rectal Surgery Trainees and Leaders

BACKGROUND

Despite recent changes in women and underrepresented minorities in medicine, there still exists large gender and racial gaps in surgical training and leadership.

OBJECTIVE

We hypothesize that gender and racial representation have improved among general and colorectal surgical trainees and leadership over the past 20 years.

DESIGN

This cross-sectional study examines gender and racial representation of general and colorectal surgery residents, colorectal faculty members, and the American Society of Colon and Rectal Surgeons Executive Council.

SETTINGS

We extracted data from the Journal of the American Medical Association Graduate Medical Education yearly reports for information on surgical residents. We used the American Society of Colon and Rectal Surgeons website and publicly available practice websites to obtain information regarding colon and rectal surgery residents, faculty members, and the American Society of Colon and Rectal Surgeons Executive Council.

MAIN OUTCOME MEASURES

We primarily focused on the gender and underrepresented minority breakdowns of general surgery residents, colorectal surgery residents, and the American Society of Colon and Rectal Surgeons Executive Council.

RESULTS

We found that between 2001 and 2021, the number of women and people identifying as underrepresented minorities increased within general surgery programs. In addition, there has been a similar increase in underrepresented minorities and women entering colorectal surgery residency programs. Finally, there has been a steady, significant increase in women representation in the American Society of Colon and Rectal Surgeons Executive Council, with a slower increase in underrepresented minorities on the council.

LIMITATIONS

The study is limited by using previously collected data and relying on publicly available profiles for gender and race information.

CONCLUSIONS

General and colon and rectal surgery have significantly increased gender and racial diversity at the training and leadership levels.

DIVERSIDAD RACIAL Y DE GNERO ENTRE LOS APRENDICES Y LDERES DE CIRUGA DE COLON Y RECTO

ANTECEDENTES: A pesar de los cambios recientes en las mujeres y las minorías subrepresentadas en la medicina, todavía existen grandes brechas de género y raza en la capacitación y el liderazgo quirúrgico.OBJETIVO: Presumimos que la representación racial y de género ha mejorado entre los pasantes y el liderazgo en cirugía general y colorrectal en los últimos 20 años.DISEÑO: Este es un estudio transversal que examina la representación racial y de género de los residentes de cirugía general y colorrectal, miembros de la facultad colorrectal y el Consejo Ejecutivo de la Sociedad Estadounidense de Cirujanos de Colon y Recto.CONFIGURACIÓN: Extrajimos datos de los informes anuales de Educación Médica para Graduados del Journal of the American Medical Association para obtener información sobre los residentes quirúrgicos. Utilizamos el sitio web de la Sociedad Estadounidense de Cirujanos de Colon y Recto, así como los sitios web de práctica disponibles públicamente para obtener información sobre los residentes de cirugía de colon y recto, miembros de la facultad y el Consejo Ejecutivo de la Sociedad Estadounidense de Cirujanos de Colon y Recto.MEDIDAS PRINCIPALES DE RESULTADO: Nos enfocamos principalmente en los desgloses de género y minorías subrepresentadas de residentes de cirugía general, residentes de cirugía colorrectal y el Consejo Ejecutivo de la Sociedad Estadounidense de Cirujanos de Colon y Recto.RESULTADOS: Encontramos que entre 2001 y 2021, la cantidad de mujeres y personas que se identificaron como minorías subrepresentadas aumentó dentro de los programas de cirugía general. Además, ha habido un aumento similar en minorías subrepresentadas y mujeres que ingresan a programas de residencia en cirugía colorrectal. Finalmente, ha habido un aumento constante y significativo en la representación de mujeres en el Consejo Ejecutivo de la Sociedad Estadounidense de Cirujanos de Colon y Recto con un aumento más lento en las minorías subrepresentadas en el consejo.LIMITACIONES: El estudio está limitado por el uso de datos recopilados previamente y por confiar en perfiles disponibles públicamente para la información de género y raza.CONCLUSIONES: La cirugía general y de colon y recto han hecho algunos avances significativos en el aumento de la diversidad racial y de género en los niveles de formación y liderazgo. (Traducción-Yesenia.Rojas-Khalil ).

Circumferential Resection Margin as Predictor of Nonclinical Complete Response in Nonoperative Management of Rectal Cancer

BACKGROUND

Short-course radiation therapy and consolidation chemotherapy with nonoperative intent has emerged as a novel treatment paradigm for patients with rectal cancer, but there are no data on the predictors of clinical complete response.

OBJECTIVE

Evaluate the predictors of clinical complete response and survival.

DESIGN

Retrospective cohort.

SETTINGS

National Cancer Institute-designated cancer center.

PATIENTS

Patients with stage I to III rectal adenocarcinoma treated between January 2018 and May 2019 (n = 86).

INTERVENTIONS

Short-course radiation therapy followed by consolidation chemotherapy.

MAIN OUTCOME MEASURES

Logistic regression was performed to assess for predictors of clinical complete response. The end points included local regrowth-free survival, regional control, distant metastasis-free survival, and overall survival.

RESULTS

A positive (+) circumferential resection margin by MRI at diagnosis was a significant predictor of nonclinical complete response (OR: 4.1, p = 0.009) when adjusting for CEA level and primary tumor size. Compared to patients with a negative (-) pathologic circumferential resection margin, patients with a positive (+) pathologic circumferential resection margin had inferior local regrowth-free survival (29% vs 87%, p < 0.001), regional control (57% vs 94%, p < 0.001), distant metastasis-free survival (43% vs 95%, p < 0.001), and overall survival (86% vs 95%, p < 0.001) at 2 years. However, the (+) and (-) circumferential resection margin by MRI subgroups in patients who had a clinical complete response both had similar regional control, distant metastasis-free survival, and overall survival of more than 90% at 2 years.

LIMITATIONS

Retrospective design, modest sample size, short follow-up, and the heterogeneity of treatments.

CONCLUSIONS

Circumferential resection margin involvement by MRI at diagnosis is a strong predictor of nonclinical complete response. However, patients who achieve a clinical complete response after short-course radiation therapy and consolidation chemotherapy with nonoperative intent have excellent clinical outcomes regardless of the initial circumferential resection margin status. See Video Abstract at http://links.lww.com/DCR/C190 .

EL MARGEN DE RESECCIN CIRCUNFERENCIAL COMO PREDICTOR NO CLNICO DE RESPUESTA COMPLETA EN EL MANEJO CONSERVADOR DEL CNCER DE RECTO

ANTECEDENTES:La radioterapia de corta duración y la quimioterapia de consolidación en el manejo conservador, han surgido como un nuevo paradigma de tratamiento, para los pacientes con cáncer de recto, lastimosamente no hay datos definitivos sobre los predictores de una respuesta clínica completa.OBJETIVO:Evaluar los predictores de respuesta clínica completa y de la sobrevida.DISEÑO:Estudio retrospectivo de cohortes.AJUSTES:Centro oncológico designado por el NCI.PACIENTES:Adenocarcinomas de recto estadio I-III tratados entre 01/2018 y 05/2019 (n = 86).INTERVENCIONES:Radioterapia de corta duración seguida de quimioterapia de consolidación.PRINCIPALES MEDIDAS DE RESULTADO:Se realizó una regresión logística para evaluar los predictores de respuesta clínica completa. Los criterios de valoración incluyeron la sobrevida libre de recidiva local, el control regional, la sobrevida libre de metástasis a distancia y la sobrevida general.RESULTADOS:Un margen de resección circunferencial positivo (+) evaluado por imagenes de resonancia magnética nuclear en el momento del diagnóstico fue un predictor no clínico muy significativo de respuesta completa (razón de probabilidades/ OR: 4,1, p = 0,009) al ajustar el nivel de antígeno carcinoembrionario y el tamaño del tumor primario. Comparando con los pacientes que presetaban un margen de resección circunferencial patológico negativo (-), los pacientes con un margen de resección circunferencial patológico positivo (+) tuvieron una sobrevida libre de recidiva local (29% frente a 87%, p < 0,001), un control regional (57% frente a 94%, p < 0,001), una sobrevida libre de metástasis a distancia (43% frente a 95%, p < 0,001) y una sobrevida global (86% frente a 95%, p < 0,001) inferior en 2 años de seguimiento. Sin embargo, los subgrupos de margen de resección circunferencial (+) y (-) evaluados por imágenes de resonancia magnética nuclear en pacientes que tuvieron una respuesta clínica completa tuvieron un control regional similar, una sobrevida libre de metástasis a distancia y una sobrevida general >90% en 2 años de seguimiento.LIMITACIONES:Diseño retrospectivo, tamaño modesto de la muestra, seguimiento corto y heterogeneidad de tratamientos.CONCLUSIONES:La afectación del margen de resección circunferencial evaluado por resonancia magnética nuclear al momento del diagnóstico es un fuerte factor predictivo no clínico de respuesta completa. Sin embargo, los pacientes que logran una respuesta clínica completa después de un curso corto de radioterapia y quimioterapia de consolidación como manejo conservador tienen excelentes resultados clínicos independientemente del estado del margen de resección circunferencial inicial. Consulte Video Resumen en http://links.lww.com/DCR/C190 . (Traducción-Dr. Xavier Delgadillo ).

Discharge Prescribing Protocol Decreases Opioids in Circulation and Does Not Increase Refills After Colorectal Surgery

BACKGROUND

Up to 10% of patients develop new, persistent opioid use after surgery. We aimed to assess our prescribing practices and patient utilization of opioids after colorectal surgery.

OBJECTIVE

This study aimed to implement an opioid-prescribing protocol that will minimize the number of postoperative opioids to decrease community circulation and persistent use by patients.

DESIGN

This was a single-institution, prospective study based on questionnaires of postoperative patients in 2019 and 2020 to determine opioid prescribing and usage patterns. Based on these preliminary results, a protocol was implemented in which patients were discharged with 5 or 15 oxycodone 5 mg equivalents based on opioid usage in the 24 hours before discharge. Patients were surveyed after protocol implementation.

SETTINGS

Our institution is a large referral center for surgical treatment of colorectal disease.

PATIENTS

Adults who underwent inpatient abdominal colorectal procedures.

MAIN OUTCOME MEASURES

End points included the number of opioids prescribed, number of prescribed opioids taken, and refill rate. Nonparametric testing was used.

RESULTS

Of 77 eligible patients, 61 were opioid naive. Preprotocol, opioid-naive patients (n = 29) were prescribed a median of 30 (interquartile range [IQR], 30-45) tablets but took only 10 (IQR, 0-10; p < 0.0001). Eighty-three percent took 20 or fewer tablets. After protocol implementation, opioid-naive patients (n = 32) were prescribed fewer tablets (median 15; IQR, 7-15; p < 0.0001) but took a similar number of tablets as the preprotocol group (median 10; IQR, 0-10; p = 0.21). The refill rate remained similar (13.8% vs 18.8%; p = 0.60). Protocol adherence was 90.6%.

LIMITATIONS

This study is limited by sample size, cohort heterogeneity, and generalizability.

CONCLUSIONS

Patients took significantly fewer opioids than were prescribed. Our protocol limited overprescribing and resulted in fewer opioids in the community without opportunity costs such as increased refills. Long-term studies are needed to assess the effects of persistent opioid use after surgery. See Video Abstract at http://links.lww.com/DCR/C93 .

FDG-PET/MRI for Nonoperative Management of Rectal Cancer: A Prospective Pilot Study

Nonoperative management (NOM) is increasingly utilized for rectal cancer patients with a clinical complete response (cCR) following total neoadjuvant therapy (TNT). The objective of this pilot study was to determine whether FDG-PET/MRI alters clinical response assessments among stage I-III rectal cancer patients undergoing TNT followed by NOM, relative to MRI alone. This prospective study included 14 subjects with new rectal cancer diagnoses. Imaging consisted of FDG-PET/MRI for initial staging, post-TNT restaging, and surveillance during NOM. Two independent readers assessed treatment response on MRI followed by FDG-PET/MRI. Inter-reader differences were resolved by consensus review. The reference standard for post-TNT restaging consisted of surgical pathology or clinical follow-up. 7/14 subjects completed post-TNT restaging FDG-PET/MRIs. 5/7 subjects had evidence of residual disease and underwent total mesorectal excision; 2/7 subjects had initial cCR with no evidence of disease after 12 months of NOM. FDG-PET/MRI assessments of cCR status at post-TNT restaging had an accuracy of 100%, compared with 71% for MRI alone, as FDG-PET detected residual tumor in 2 more subjects. Inter-reader agreement for cCR status on FDG-PET/MRI was moderate (kappa, 0.56). FDG-PET provided added value in 82% (9/11) of restaging/surveillance scans. Our preliminary data indicate that FDG-PET/MRI can detect more residual disease after TNT than MRI alone, with the FDG-PET component providing added value in most restaging/surveillance scans.

Perioperative Complications After Proctectomy for Rectal Cancer: Does Neoadjuvant Regimen Matter?

OBJECTIVE

Investigate the association between neoadjuvant treatment strategy and perioperative complications in patients undergoing proctectomy for nonmetastatic rectal cancer.

SUMMARY OF BACKGROUND DATA

Neoadjuvant SC-TNT is an alternative to neoadjuvant CRT for rectal cancer. Some have argued that short-course radiation and extended radiation-to-surgery intervals increase operative difficulty and complication risk. However, the association between SC-TNT and surgical complications has not been previously investigated.

METHODS

This single-center retrospective cohort study included patients undergoing total mesorectal excision for nonmetastatic rectal cancer after SC-TNT or CRT between 2010 and 2018. Univariate analysis of severe POM and multiple secondary outcomes, including overall POM, intraoperative complications, and resection margins, was performed. Logistic regression of severe POM was also performed.

RESULTS

Of 415 included patients, 156 (38%) received SC-TNT and 259 (62%) received CRT. The cohorts were largely similar, though patients with higher tumors (69.9% vs 47.5%, P < 0.0001) or node-positive disease (76.9% vs 62.6%, P = 0.004) were more likely to receive SC-TNT. We found no difference in incidence of severe POM (9.6% SC-TNT vs 12.0% CRT, P = 0.46) or overall POM (39.7% SC-TNT vs 37.5% CRT, P = 0.64) between cohorts. Neoadjuvant regimen was also not associated with a difference in severe POM (odds ratio 0.42, 95% confidence interval 0.04-4.70, P = 0.48) in multivariate analysis. There was no significant association between neoadjuvant regimen and any secondary outcome.

CONCLUSION

In rectal cancer patients treated with SC-TNT and proctectomy, we found no significant association with POM compared to patients undergoing CRT. SC-TNT does not significantly increase the risk of POM compared to CRT.

Clinical Complete Response in Patients With Rectal Adenocarcinoma Treated With Short-Course Radiation Therapy and Nonoperative Management

PURPOSE

This study aimed to determine the clinical efficacy and safety of nonoperative management (NOM) for patients with rectal cancer with a clinical complete response (cCR) after short-course radiation therapy and consolidation chemotherapy.

METHODS AND MATERIALS

Patients with stage I-III rectal adenocarcinoma underwent short-course radiation therapy followed by consolidation chemotherapy between January 2018 and May 2019 (n = 90). Clinical response was assessed by digital rectal examination, pelvic magnetic resonance imaging, and endoscopy. Of the patients with an evaluable initial response, those with a cCR (n = 43) underwent NOM, and those with a non-cCR (n = 43) underwent surgery. The clinical endpoints included local regrowth-free survival, regional control, distant metastasis-free survival, disease-free survival, and overall survival.

RESULTS

Compared with patients with an initial cCR, patients with initial non-cCR had more advanced T and N stage (P = .05), larger primary tumors (P = .002), and more circumferential resection margin involvement on diagnostic magnetic resonance imaging (P < .001). With a median follow-up of 30.1 months, the persistent cCR rate was 79% (30 of 38 patients) in the NOM cohort. The 2-year local regrowth-free survival was 81% (95% confidence interval [CI], 70%-94%) in the initial cCR group, and all patients with local regrowth were successfully salvaged. Compared with those with a non-cCR, patients with a cCR had improved 2-year regional control (98% [95% CI, 93%-100%] vs 85% [95% CI, 74%-97%], P = .02), distant metastasis-free survival (100% [95% CI, 100%-100%] vs 80% [95% CI, 69%-94%], P < .01), disease-free survival (98% [95% CI, 93%-100%] vs 71% [95% CI, 59%-87%], P < .01), and overall survival (100% [95% CI, 100%-100%] vs 88% [95% CI, 79%-98%], P = .02). No late grade 3+ gastrointestinal or genitourinary toxicities were observed in the patients who underwent continued NOM.

CONCLUSIONS

Short-course radiation therapy followed by consolidation chemotherapy may be a feasible organ preservation strategy in rectal cancer. Additional prospective studies are necessary to evaluate the safety and efficacy of this approach.

Travel Time to a High Volume Center Negatively Impacts Timing of Care in Rectal Cancer

BACKGROUND

Regionalization of rectal cancer surgery may lead to worse disease free survival owing to longer travel time to reach a high volume center yet no study has evaluated this relationship at a single high volume center volume center.

MATERIALS AND METHODS

This was a retrospective review of rectal cancer patients undergoing surgery from 2009 to 2019 at a single high volume center. Patients were divided into two groups based on travel time. The primary outcome was disease-free survival (DFS). Additional outcomes included treatment within 60 d of diagnosis, completeness of preoperative staging, and evaluation by a colorectal surgeon prior to initiation of treatment.

RESULTS

A lower proportion of patients with long travel time began definitive treatment within 60 d of diagnosis (74.0% versus 84.0%, P= 0.01) or were seen by the treating colorectal surgeon before beginning definitive treatment (74.8% versus 85.4%, P < 0.01). On multivariable logistic regression analysis, patients with long travel time were significantly less likely to begin definitive treatment within 60 d of diagnosis (OR = 0.54; 95% CI = 0.31-0.93) or to be evaluated by a colorectal surgeon prior to initiating treatment (OR = 0.45; 95% CI = 0.25-0.80). There were no significant differences in DFS based on travel time.

CONCLUSIONS

Although patients with long travel times may be vulnerable to delayed, lower quality rectal cancer care, there is no difference in DFS when definitive surgery is performed at a high volume canter. Ongoing research is needed to identify explanations for delays in treatment to ensure all patients receive the highest quality care.

Factors affecting local regrowth after watch and wait for patients with a clinical complete response following chemoradiotherapy in rectal cancer (InterCoRe consortium): an individual participant data meta-analysis

BACKGROUND

In patients with rectal cancer who achieve clinical complete response after neoadjuvant chemoradiotherapy, watch and wait is a novel management strategy with potential to avoid major surgery. Study-level meta-analyses have reported wide variation in the proportion of patients with local regrowth. We did an individual participant data meta-analysis to investigate factors affecting occurrence of local regrowth.

METHODS

We updated search results of a recent systematic review by searching MEDLINE and Embase from Jan 1, 2016, to May 5, 2017, and used expert knowledge to identify published studies reporting on local regrowth in patients with rectal cancer managed by watch and wait after clinical complete response to neoadjuvant chemoradiotherapy. We restricted studies to those that defined clinical complete response using criteria equivalent to São Paulo benchmarks (ie, absence of residual ulceration, stenosis, or mass within the rectum on clinical and endoscopic examination). The primary outcome was 2-year cumulative incidence of local regrowth, estimated with a two-stage random-effects individual participant data meta-analysis. We assessed the effects of clinical and treatment factors using Cox frailty models, expressed as hazard ratios (HRs). From these models, we derived percentage differences in mean θ as an approximation of the effect of measured covariates on between-centre heterogeneity. This study is registered with PROSPERO, number CRD42017070934.

FINDINGS

We obtained individual participant data from 11 studies, including 602 patients enrolled between March 11, 1990, and Feb 13, 2017, with a median follow-up of 37·6 months (IQR 25·0-58·7). Ten of the 11 datasets were judged to be at low risk of bias. 2-year cumulative incidence of local regrowth was 21·4% (random-effects 95% CI 15·3-27·6), with high levels of between-study heterogeneity (I²=61%). We noted wide between-centre variation in patient, tumour, and treatment characteristics. We found some evidence that increasing cT stage was associated with increased risk of local regrowth (random-effects HR per cT stage 1·40, 95% CI 1·00-1·94; p_trend=0·048). In a subgroup of 459 patients managed after 2008 (when pretreatment staging by MRI became standard), 2-year cumulative incidence of local regrowth was 19% (95% CI 13-28) for stage cT1 and cT2 tumours, 31% (26-37) for cT3, and 37% (21-60) for cT4 (random-effects HR per cT stage 1·50, random-effects 95% CI 1·03-2·17; p_trend=0·0330). We estimated that measured factors contributed 4·8-45·3% of observed between-centre heterogeneity.

INTERPRETATION

In patients with rectal cancer and clinical complete response after chemoradiotherapy managed by watch and wait, we found some evidence that increasing cT stage predicts for local regrowth. These data will inform clinician-patient decision making in this setting. Research is needed to determine other predictors of a sustained clinical complete response.

FUNDING

None.

Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015

REASONS FOR PERFORMING STUDY

Injury to the superficial digital flexor tendon (SDFT) is common in equids, with a high risk of re-injury associated with changes in tendon stiffness. In vivo measurement of limb stiffness has been shown to correlate with tendon stiffness after injury [1] but requires kinematic analysis which is impractical in a clinical setting. We have developed a simple system for measuring limb stiffness statically, which could be used as a tool for monitoring SDFT healing.

OBJECTIVES

To validate a goniometric measurement of limb stiffness.

STUDY DESIGN

Cross sectional study.

METHODS

Initially, forelimb stiffness indices were determined at the walk for 6 equids using a validated kinematic analysis [1]. Limb stiffness indices were then calculated using portable floor scales to record ground reaction force (GRF), and an electrogoniometer to record metacarpophalangeal joint angle. Goniometric limb stiffness indices were subsequently measured in 11 horses ranging from 2 to 20 years of age, with no clinical evidence of SDFT injury. Strength and significance of correlation and agreement between the measurement methods was assessed and association between limb stiffness, limb (left vs. right), weight and age of horse and were calculated.

RESULTS

There were strong positive correlations between GRF and joint angle (R(2) = 0.98) and between the static and kinematic methods (R = 0.78, P<0.01). There was a positive correlation between limb stiffness and weight (R(2) = 0.85, P<0.01), but no association with age or limb.

CONCLUSIONS

This study validated the measurement of limb stiffness in a clinical setting. The positive correlation of limb stiffness and weight supports the theory of an optimised limb spring [2] for energy-efficient cursorial locomotion which may, in turn, provide a clinically-relevant measure of running efficiency and therefore the quality of tendon healing post injury. Ethical animal research: Owner consent was obtained.

SOURCE OF FUNDING

None. Competing interests: None declared.

Surveillance after neoadjuvant therapy in advanced rectal cancer with complete clinical response can have comparable outcomes to total mesorectal excision

PURPOSE

While the standard of care for patients with rectal cancer who sustain a complete clinical response (cCR) to chemoradiotherapy (CRT) remains proctectomy with total mesorectal excision, data suggests that non-operative management may be a safe alternative. The purpose of this study is to compare outcomes between patients treated with CRT that attained a cCR and opted for a vigilant surveillance to those of the patients who had a complete pathologic response (cPR) following proctectomy.

METHOD

This is a retrospective review of patients treated for adenocarcinoma of the rectum who achieved either a cCR or a cPR following CRT. Patients with a cCR were enrolled in an active surveillance program which included regularly scheduled exams, proctoscopy, serum carcinoembryonic antigen (CEA), endorectal ultrasound, and cross-sectional imaging. Outcomes were compared to those patients who underwent proctectomy with a cPR. Our primary outcome measures were post-treatment complications, recurrence, and survival.

RESULTS

We reviewed 18 patients who opted for surveillance after cCR and 30 patients who underwent proctectomy after a cPR. No non-operative patients had a documented treatment complication, while 17 patients with cPR suffered significant morbidity. There were two recurrences in the active surveillance group, one local and once distant, both treated by salvage resection with no associated mortality at 54 and 62 months. In the cPR group, one patient had a distant recurrence 24 months after surgery which was managed non-operatively. This patient died of unrelated causes 35 months after surgery.

CONCLUSIONS

Active surveillance can be a safe option that avoids the morbidity associated with proctectomy and preserves oncologic outcomes.

Identifying optimal parameters for quantification of changes in pelvic movement symmetry as a response to diagnostic analgesia in the hindlimbs of horses

REASONS FOR PERFORMING STUDY

Subjective evaluation of the response to diagnostic analgesia of hindlimb lameness is influenced by expectation bias. Quantification of pelvic movement with inertial measurement units is possible, but it is unclear which measure of movement symmetry best reflects the changes seen after diagnostic analgesia.

OBJECTIVES

To test our hypothesis that objective measures closely relating to those used for subjective visual lameness scoring (quantifying the difference between sacral upward or downward movement or between movement amplitudes of the left and right tubera coxae) would show the largest and most consistent response.

STUDY DESIGN

Retrospective analysis of subjective and objective clinical lameness data.

METHODS

Thirteen horses with hindlimb lameness underwent visual lameness scoring and independent gait assessment with inertial measurement units. Established objective measures were calculated and changes before/after diagnostic analgesia regressed against the change in lameness grade. Slopes of regression lines were calculated and confidence intervals assessed.

RESULTS

All objective parameters showed variation between horses and across lameness grades. The following 3 measures documented a consistent increase in symmetry for each grade of change in lameness score: difference between sacral displacement minima; upward movement difference; and range of motion difference between the tubera coxae.

CONCLUSIONS

Several pelvic parameters are suitable for objective quantification of changes after diagnostic analgesia in hindlimb-lame horses. A change of 9-13% per lameness grade can be expected. Upward movement of the tubera coxae is the most sensitive objective measure for quantifying a response to diagnostic analgesia. However, when assessed visually, this measure requires simultaneous focusing on pelvic and limb movements. Other parameters that show a similar response might be more easily perceived, requiring only assessment of tubera coxae range of motion or downward displacement of the sacrum without simultaneous focus on limb movement.

The effect of intralesional injection of bone marrow derived mesenchymal stem cells and bone marrow supernatant on collagen fibril size in a surgical model of equine superficial digital flexor tendonitis

REASONS FOR PERFORMING STUDY

Collagen fibril size is decreased in repair tissue following tendon injury compared to normal tendon matrix in horses. Mesenchymal stem cells have been suggested to promote regeneration of tendon matrix rather than fibrotic repair following injury, although this concept remains unproven.

OBJECTIVES

To explore the hypothesis that implantation of autologous mesenchymal stem cells derived from bone marrow into a surgically created central core defect in the superficial digital flexor tendon (SDFT) of horses would induce the formation of a matrix with greater ultrastructural similarities to tendon matrix than the fibrotic scar tissue formed in control defects.

METHODS

Tissue was collected 16 weeks after induction of injury and 12 weeks after treatment from normal and injured regions of control and treated limbs of 6 horses and examined using transmission electron microscopy. Collagen fibril diameters were measured manually with image analysis software and surface areas calculated. Three parameters assessed for normal and injured tissue were mass average diameter (MAD), collagen fibril index (CFI) and the area dependent diameter (ADD).

RESULTS

Normal regions from both treated and control limbs displayed higher MAD and CFI values, as well as a characteristic bimodal distribution in fibril size. Injured regions from both treated and control limbs displayed significantly lower MAD and CFI values, as well as a unimodal distribution in fibril size. There were no significant differences between treated and control limbs for any of the parameters assessed.

CONCLUSIONS

Intralesional injection of autologous bone marrow derived mesenchymal stem cells had no measurable effect on the fibril diameter of collagen in healing tissue in the SDFT of this experimental model 16 weeks after injury.

POTENTIAL RELEVANCE

Favouring matrix regeneration over fibrotic repair may not be the mechanism by which autologous mesenchymal stem cells assist healing of tendon injury.

The effect of exercise regimens on racing performance in National Hunt racehorses

REASONS FOR PERFORMING STUDY

A previous study has identified exercise undertaken during training to be associated with racing performance in flat racehorses. However, no such studies have been conducted in National Hunt (NH) horses.

AIM

To determine whether exercise undertaken during training is associated with racing performance in NH racehorses.

METHODS

Data were collected as part of a larger study investigating injury occurrence in NH racehorses. Race records and daily exercise data were obtained from NH racehorses at 14 training yards. Canter, gallop and race distances accumulated in the 30 days preceding a 'case race' were calculated. Associations between exercise-, horse- and race-level variables and the odds of winning, winning prize money, being pulled up and falling were identified using mixed effects logistic regression.

RESULTS

Data from 4444 races run by 858 horses were included in analyses. Horses accumulating longer canter distances in the preceding 30 days were more likely to win or win prize money and less likely to be pulled-up. Horses accumulating longer race distances in a 30 day period were more likely to win, whilst those accumulating longer gallop distances in a 30 day period were more likely to win prize money. Horses that had jump-schooled in the preceding 30 days were more likely to fall during the race than those that had not. Trainer and horse were associated with racing performance after adjusting for exercise.

CONCLUSIONS

Results from this study suggest that NH race performance may be improved through modification of exercise regimens. After controlling for the abilities of individual trainers and horses and conditions of the case race, horses accumulating longer exercise distances in the 30 days preceding a race were more likely to be successful. However, horses that had jump-schooled in the 30 days preceding a race were more likely to fall.

Effect of age at presentation on outcome following arthroscopic debridement of subchondral cystic lesions of the medial femoral condyle: 85 horses (1993-2003)

REASONS FOR PERFORMING STUDY

Subchondral cystic lesions of the medial femoral condyle (SCMFC) are well documented in horses < or =3 years; arthroscopic debridement or enucleation of the cyst is currently the surgical treatment of choice. However, studies of occurence and outcome following surgery in older horses are lacking.

OBJECTIVE

To identify factors important in outcome for horses with SCMFC treated by arthroscopic debridement.

HYPOTHESIS

Age of horse at presentation has a significant influence on return to work following arthroscopic treatment for SCMFC. Clinical and diagnostic findings are also significant with respect to prognosis.

METHODS

A retrospective review of medical records from 6 equine referral centres identified 85 horses that underwent arthroscopic debridement of SCMFC. Clinical examination, radiographic and arthroscopic findings were analysed together with follow-up data. Univariable analysis and multivariable logistic regression models were used to determine factors affecting return to soundness. Event-time analysis was performed to evaluate return to work.

RESULTS

Older horses (>3 years) were less likely to return to soundness (P = 0.02) or to work (P = 0.04) than younger horses (< or = 3 years). Of 39 horses age 0-3 years, 25 (64%, 95% CI 49-79%) returned to soundness. Of 46 horses age >3 years, 16 (35%,95% CI 21-49%) returned to soundness. In addition, cartilage damage at sites other than the SCMFC negatively affected prognosis (P = 0.05). The hospital where treatment was performed had no influence on return to soundness.

CONCLUSIONS

Older horses carry a worse prognosis for both return to soundness and return to work.

POTENTIAL RELEVANCE

It is important for clients to be made aware of the difference in outcome between age groups.

Microdisplacement printing

We describe a new patterning technique that employs microcontact printing to replace preformed labile self-assembled monolayers (SAMs) selectively; we call this "microdisplacement printing". We demonstrate that this technique results in ordered molecular regions of both the patterning ("displacing") molecule as well as the remnant labile film, here 1-adamantanethiolate. The existence of the 1-adamantanethiolate SAM before patterning hinders lateral surface diffusion of the patterning molecules, and therefore permits the use of molecules that are otherwise too mobile to pattern by other methods.

Retrospective study of 24 cases of septic calcaneal bursitis in the horse

REASONS FOR PERFORMING STUDY

Wounds to the plantar aspect of the tarsus present a diagnostic and treatment challenge. This study was undertaken to describe specific features of traumatic wounds involving the calcaneal bursa, with a view to determining which clinical examination findings and diagnostic tests results could provide reliable indicators of prognosis.

OBJECTIVES

To report clinical presentation, diagnostic findings, treatment and outcome of 24 cases of septic calcaneal bursitis; and to determine the importance of the involvement of specific anatomical structures in relation to the prognosis for survival and return to athletic function.

METHODS

Records of 24 horses that had suffered traumatic wounds involving the calcaneal bursae were reviewed and divided into 3 groups, based on the bursa involved and presence or absence of involvement of the tuber calcanei. Clinical, diagnostic imaging and surgical findings were recorded for each case. Differences between groups and outcome were examined for significance with Chi-squared, Fisher's Exact or Kruskal-Wallis tests, as appropriate.

RESULTS

Wounds involving only the subcutaneous bursa had an excellent prognosis for survival. Seventy-five percent of horses with wounds involving the intertendinous calcaneal bursa survived. Involvement of the tuber calcanei presented a fair to guarded prognosis, with only 44% of horses with involvement of this structure surviving.

CONCLUSIONS

In contrast to other studies of septic synovial structures, the time between initial injury and referral did not affect the outcome. Correct identification of invasion of the calcaneal bursa(e) and/or tuber calcanei in wounds to the plantar aspect of the tarsus allows for more accurate pronostication. Damage to the tuber calcanei presents a poorer prognosis than for cases that involve only the soft tissue structures in the region.

POTENTIAL RELEVANCE

This study demonstrates the importance of correct anatomical identification of structures involved in wounds in the region of the calcaneal bursa. The use of radiography, ultrasonography and synoviocentesis are essential in these cases to provide the most appropriate treatment for the horse and accurate prognosis for the owner.

Confocal laser scanning microscope study of cytokeratin immunofluorescence differences between villous and extravillous trophoblast: Cytokeratin downregulation in pre-eclampsia

Pre-eclampsia is a disease characterized by failures in interstitial implantation. One product of the implantation process is the basal plate; a structure whose complexity makes it hard to fully appreciate the pathological changes in significant diseases of pregnancy. This article describes our use of CLSM immunofluorescence to examine the cytokeratin composition of the cells of trophoblastic origin in the term placental basal plate. Large differences in the content of the structural polymeric protein were compared using analysis of digital images. We show that greater pancytokeratin immunofluorescence is observed in extravillous cytotrophoblast cells as compared with villous trophoblast. There is a >30-fold difference in the mean area percent of the most intensely immunofluorescent pixels in the tissue containing these cells. This is a very high, statistically significant difference as defined by the Wilcoxon Signed Ranks Test Asym. Sig. (two-tailed): P < 0.001. The most invasive population of cells of the trophoblast lineage (the extravillous trophoblast) exhibits a significant reduction in cytokeratin immunofluorescence when comparisons of healthy and pre-eclamptic pregnancies are made. This ratio was 2.4:1. It was tested using the Mann-Whitney U-test. From healthy to pre-eclamptic the reduction was from mean rank 83.42((healthy)) to 51.13((pre-eclamptic)). The difference was very highly statistically significant (n = 53 + 75 = 128; U = 984.500; Z = -4.852; P < 0.001). There was also less cytokeratin-related immunofluorescence in villous trophoblast when healthy villi were compared with pre-eclamptic villi. The observed alterations in trophoblastic cytoskeletal components are expected to damage the anchorage and motility of cells. The extravillous trophoblast is known to be necessary for implantation. This leads to a cellular hypothesis of the failure of implantation resulting in reduced depth of uterine invasion and failure to adapt the spiral arterioles for low-pressure perfusion of the intervillus space, two well-known features of pre-eclampsia. The reduction in cytokeratin-related immunofluorescence in the villus trophoblast seen on comparing healthy term placentae with those from pre-eclamptics implies that the trophoblast is a weaker epithelial layer in the hypertensive pregnancy. This could account for the rise in deported trophoblast associated with pre-eclampsia. Deported trophoblast has been invoked as the systemic messenger that leads to generalized maternal hypertension seen in this condition.

Healthy and pre-eclamptic placental basal plate lining cells: Quantitative comparisons based on confocal laser scanning microscopy

Immunocytochemical confocal laser scanning microscope images of the monolayer of cells lining the intervillus space at the basal plate of term placentae were analysed using stereology. Immunoreactively-distinct regions of this mosaic layer were measured. In basal plate from healthy pregnancies, trophoblast epithelium occupied 18.91% of the surface area and endothelium 60.81%. In pre-eclampsia the equivalent areas were 15.57% and 67.63%. Acellular fibrinoid covers the remaining area and this component decreases in area in pre-eclampsia. The statistically significant increase in the cellular endothelial compartment may be relevant to the hypertensive pathology of pre-eclampsia as endothelial signalling plays a major role in regulation of blood pressure.

The distribution of cartilage oligomeric matrix protein (COMP) in equine carpal articular cartilage and its variation with exercise and cartilage deterioration

Based on previous studies where tendons receiving the most load have been shown to have the highest levels of cartilage oligomeric matrix protein (COMP), we hypothesized that COMP distribution in articular cartilage may be influenced by mechanical loading. This investigation aimed (a) to describe the pattern of COMP immunoreactivity in middle carpal joint cartilage of two-year-old Thoroughbred horses; (b) to determine topographical variations; (c) to compare high (group 1) and low (group 2) intensity training and (d) to describe COMP immunoreactivity at sites with early osteoarthritis. Group 1 (n =6) underwent a 19 week high-intensity treadmill training programme and group 2 (n =6) were given daily walking until euthanasia. Dorsal and palmar sites on radial and third carpal articular surfaces were prepared. Immunohistochemistry was performed with polyclonal rabbit anti-equine COMP antiserum using a biotin-streptavidin/peroxidase method. Results showed: (a) intracellular immunoreactivity was present in all cartilage zones, but the distribution of COMP staining within the matrix varied between cartilage zones; (b) differences in distribution between sites were not observed, but total COMP levels in exercised horses (n =2) did vary between sites with dorsal sites containing less COMP than palmar sites on the radial, intermediate and third carpal lateral facet; (c) group 1 cartilage showed marked interterritorial distribution in the deep layer compared to group 2 where staining was more generalized throughout the matrix and (d) fibrillated cartilage showed increased local immunoreactivity in the matrix. These findings demonstrate zonal variations in equine COMP distribution which may be influenced by loading.

Use of a bioabsorbable implant for the repair of severed digital flexor tendons in four horses

A new bioabsorbable implant composed of poly-L-lactic acid was used to repair the severed digital flexor tendons of four horses. The limbs were immobilised with distal casts which were changed after six to eight weeks and removed after 12 to 16 weeks. The horses were followed clinically and ultrasonographically for from seven to 19 months after the surgery. The ultrasonographic examination after the cast had been removed showed that the implants had been well incorporated into scar tissue. Two of the horses were mildly lame at the trot seven months after the surgery, but had returned to work after 12 months. The other two horses are still lame. No complications were observed with the implant.

Treatment of sepsis in the small tarsal joints of 11 horses with gentamicin-impregnated polymethylmethacrylate beads

Gentamicin-impregnated polymethylmethacrylate beads were used to treat infective arthritis in the small tarsal joints of 11 severely lame horses. Under general anaesthesia, between five and 10 beads were placed into a 7 to 8 mm tract drilled across the affected joint and, in all except one horse, they were left in place for 14 days. Two of the horses were euthanased for reasons other than persistent tarsal joint sepsis, but the other nine survived and seven of them returned to their previous level of athletic performance.

Sequence heteroplasmy of D-loop and rRNA coding regions in mitochondrial DNA from Holstein cows of independent maternal lineages

A mitochondrial DNA (mtDNA) fragment containing the D-loop, phenylalanine tRNA, valine tRNA, and 12S and 16 rRNA genes was cloned and sequenced from 36 cows of 18 maternal lineages to identify the polymorphic sites within those regions and to detect the existence of heteroplasmic mtDNA in cows. Seventeen variable sites were observed within the D-loop and rRNA coding regions of bovine mtDNA within a 2.5-kb span. The hypervariable sites in the D-loop and rRNA coding regions were identified at nucleotide positions 169, 216, and 1594. Heteroplasmic mtDNA (variable mtDNA within a tissue) existed extensively in cows and was detected within the above regions in 11 of 36 cows sequenced. The insertion, deletion, and nucleotide transversion polymorphisms were found only in homopolymer regions. Heteroplasmy was observed frequently and seemingly is persistent in cattle. Though heteroplasmy was demonstrated, most lineages and mtDNA sites showed no heteroplasmy.

Superficial digital flexor tendonitis in the horse

The superficial digital flexor tendon (SDFT) is an elastic structure that during maximal exercise appears to operate close to its functional limits. The biomechanical and biochemical responses to exercise, injury, and healing are still poorly understood but ongoing research is providing valuable new information which is addressed in this review. It appears that the SDFT matures early, after which time it has limited ability to adapt to stress and undergoes progressive degeneration. Focal hypocellularity, collagen fibril degeneration, selective fibril loading and alterations in the noncollagenous matrix occur primarily within the central core region of the midmetacarpal segment. Current treatment strategies have had equivocal results in returning animals to optimal athletic activity. To date it would seem that progressive rehabilitation programmes coupled with regular ultrasonographic evaluations are a cost-effective and comparable strategy when compared to surgical treatment methods. Recent interest in pharmacological modulation of intrinsic healing of collagenous structures has led to the investigation of various growth factors as potential therapeutic aids in the healing of tendon injuries. However, one of the major goals in tendon research, and one which holds the most optimism for success in the immediate future, is the prevention of tendon injuries.

The Arabidopsis dnd1 "defense, no death" gene encodes a mutated cyclic nucleotide-gated ion channel

Gene-for-gene disease resistance typically includes a programmed cell death response known as the hypersensitive response (HR). The Arabidopsis thaliana dnd1 mutant was previously isolated as a line that failed to produce the HR in response to avirulent Pseudomonas syringae pathogens; plants homozygous for the recessive dnd1-1 mutation still carry out effective gene-for-gene resistance. The dnd1-1 mutation also causes constitutive systemic resistance and elevated levels of salicylic acid. In the present study, a positional cloning approach was used to isolate DND1. DND1 encodes the same protein as AtCNGC2, a cyclic nucleotide-gated ion channel of previously unknown organismal function that can allow passage of Ca(2+), K(+) and other cations [Leng, Q., Mercier, R. W., Yao, W. & Berkowitz, G. A. (1999) Plant Physiol. 121, 753-761]. By using a nahG transgene, we found that salicylic acid is required for the elevated resistance caused by the dnd1 mutation but that removal of salicylic acid did not completely eliminate the dwarf and loss-of-HR phenotypes of mutant dnd1 plants. A stop codon that would severely truncate the DND1 gene product was identified in the dnd1-1 allele. This demonstrates that broad-spectrum disease resistance and inhibition of the HR can be activated in plants by disruption of a cyclic nucleotide-gated ion channel.

Chandra X-Ray Observatory Arcsecond Imaging of the Young, Oxygen-rich Supernova Remnant 1E 0102.2-7219

We present observations of the young, oxygen-rich supernova remnant 1E 0102.2-7219 taken by the Chandra X-Ray Observatory during its orbital activation and checkout phase. The boundary of the blast-wave shock is clearly seen for the first time, allowing the diameter of the remnant and the mean blast-wave velocity to be determined accurately. The prominent X-ray bright ring of material may be the result of the reverse shock encountering ejecta; the radial variation of O vii versus O viii emission indicates an ionizing shock propagating inward, possibly through a strong density gradient in the ejecta. We compare the X-ray emission with Australia Telescope Compact Array 6 cm radio observations (Amy & Ball) and with archival Hubble Space Telescope [O iii] observations. The ring of radio emission is predominantly inward of the outer blast wave, which is consistent with an interpretation of synchrotron radiation originating behind the blast wave but outward of the bright X-ray ring of emission. Many (but not all) of the prominent optical filaments are seen to correspond to X-ray bright regions. We obtain an upper limit of approximately 9x1033 ergs s-1 (3 sigma) on any potential pulsar X-ray emission from the central region.

Federation of the Person Identification Service between enterprises

The Person Identification Service (PIDS) is a standard that has been adopted by the Object Management Group for managing identities of persons within a particular domain. That standard includes an interface that supports the ability to connect multiple PIDS servers together in a federated manner. The specification leaves great flexibility as to how to accomplish the federation. In this paper, we examine some of the federated approaches being considered by the Government Computer-based Patient Record Framework (G-CPR) project and discuss their advantages and disadvantages and the details of a specific, scalable approach to federation.

Cartilage oligomeric matrix protein (COMP) levels in digital sheath synovial fluid and serum with tendon injury

Cartilage oligomeric matrix protein (COMP) is a noncollagenous extracellular matrix protein found predominantly in cartilage, but also in tendon, ligament and meniscus. Studies in man have demonstrated that it may be used as a prognostic marker in rheumatoid arthritis and osteoarthritis. The present study investigated whether tendon injury contributes to serum and tendon sheath synovial fluid levels of COMP in horses. COMP levels, analysed by competitive ELISA, in the digital sheath synovial fluid were more than 10-fold higher than in the serum. Levels were significantly raised when tendon damage or sepsis was present within the tendon sheath but showed only mild, statistically insignificant, elevation in cases of tenosynovitis alone. COMP concentrations in serum were found to vary with age. Foals (age < or = 1 year) had significantly (P<0.001) higher levels in comparison to older control horses. Total COMP concentrations in an age-matched group with tendinitis were not significantly different from the control group. Measurements of COMP levels in tendon sheath synovial fluid are therefore useful in depicting processes in tendon tissue, while elevated serum levels are likely to be more representative of joint disease than tendinitis.

Age-related changes and effect of exercise on the molecular composition of immature equine superficial digital flexor tendons

To test the hypothesis that exercise at very young age may influence the eventual molecular composition (and hence the biomechanical properties) of tendon tissue in the horse, 43 Dutch Warmblood foals were allotted to 3 differently exercised groups (box-rest, box-rest with training and pasture exercise). Twenty-four superficial digital flexor tendons (SDFTs) were collected at age 5 months (8 from each exercise group) and the others were obtained at 11 months after an additional period of light exercise that was equal for all remaining foals and was intended to see if any induced changes would be reversible or not. Significant changes in DNA content (cellularity), hyaluronic acid (HA) and polysulphated glycosaminoglycans (PSGAGs) were found after the 5 month period of different exercise regimens. There was a tendency towards an exercise-related effect on hydroxylysine content and number of hydroxylysylpyridinoline (HP) crosslinks. Levels of Cartilage Oligomeric Matrix Protein (COMP), measured by homologous inhibition ELISA, showed significant differences at 5 months and were highest in foals kept at pasture and lowest in foals maintained in a box but given enforced exercise. At 11 months, the biochemical parameters of the tendons from the foals of the former box-rest and pasture groups became similar, indicating the capacity of the immature tendon to recover from a retarded development. However, the ratio of PSGAGs per unit of DNA of the former training group was significantly lower than those from the other groups, suggesting that the training regimen in this study had a lasting negative effect on the tenocytes resulting in a decrease of the production of PSGAGs. Therefore, inappropriate or excessive exercise may damage developing tendon, with limited recovery after normalising the exercise level. These possibly deleterious effects of a training regimen on tendon development may be important for the management of young would-be equine athletes.

Treadmill exercise-induced tendon hypertrophy: assessment of tendons with different mechanical functions

The equine superficial digital flexor tendon (SDFT) functions as an energy store during high-speed gaits reducing the energetic cost of locomotion. To enable the SDFT to function effectively, the appropriate mechanical properties are essential. We tested the hypothesis that the SDFT does not undergo gross hypertrophy in response to high-intensity exercise whereas tendons not involved in energy storage undergo adaptive hypertrophy. Two groups (n = 6) of Thoroughbred fillies were trained at high-intensity on a high-speed equine treadmill for 5 months (short-term study) or 18 months (long-term study). Age-matched groups (n = 6) of horses undertook low-intensity exercise only for the same time period. Throughout the short-term study the SDFT and deep digital flexor tendon (DDFT) were ultrasonograpically scanned at mid-metacarpal level and cross-sectional area (CSA) calculated. At the end of the short-term study (horse age = 2 years) and long-term study (horse age = 3 years) the left SDFT, DDFT, suspensory ligament (SL) and common digital extensor tendon (CDET) were harvested and CSA calculated. Comparison of the DDFT from 2- and 3-year-old horses revealed an age-related increase in CSA which was confirmed by ultrasonographs. Post mortem analysis showed a significant hypertrophy of the CDET with high-intensity training in the short-term study (younger horses). CSA did not differ significantly between training groups for any of the structures following long-term training. These results suggest a structure specific hypertrophic response to the imposed training regime.

Should equine athletes commence training during skeletal development?: changes in tendon matrix associated with development, ageing, function and exercise

In human athletes, conditioning, training and competition are commenced before skeletal maturity. Yet in equine athletics, racing of young (age 2 years) horses remains contentious. Tendon injury persists as major causes of wastage in equine athletes. Minimising injury and associated welfare issues could involve a radical approach to the timing and implementation of conditioning and training. Tendons were examined from Thoroughbreds, Dutch Warmblood foals, working horses and also a group of wild horses to evaluate effects of age, function and exercise. Gross mechanical properties did not differ significantly with age or exercise, but showed a high variance within each group. Mechanical properties of tendon tissue showed significant differences as a function of age and location. The collagen fibril crimp angle and length showed a regional reduction in the central core with exercise and age, with a synergistic effect. Regional differences in collagen fibril diameter were seen in long-term exercised older horses, but not in short-term exercised, or younger, horses. The higher proportion of small fibrils in the central region of the long-term exercised horses did not correlate with new collagen formation and therefore appear to result from disassembly of the larger diameter fibrils. Fibril diameter distributions were influenced by exercise regimens in the growing foal. Changes in molecular composition occurred in longer-term exercise and older horses, in the centre of the tendon, with higher levels of type III collagen and changes in glycosaminoglycan (GAG) content. Cartilage Oligomeric Matrix Protein (COMP) levels also appear to be modulated by age, function and superimposition of exercise. These changes were all exacerbated with age and exercise, suggesting appropriate exercise in young horses may lead to a lower incidence of injury than in older horses. An hypothesis is advanced that immature tendon can respond to exercise while mature tendon has limited, if any, ability to do so. These findings support potentially controversial earlier conditioning and racing of younger, rather than older, equine athletes.

The distribution of cartilage oligomeric matrix protein (COMP) in tendon and its variation with tendon site, age and load

A protein prominent in guanidine hydrochloride extracts of adult bovine and equine digital flexor tendons was confirmed to be Cartilage Oligomeric Matrix Protein (COMP) by non-reducing and reducing SDS-PAGE, reaction with rabbit anti-COMP polyclonal antiserum on Western blots, trypsin digestion followed by HPLC on a C2/C18 column, and identification of COMP mRNA from tendon on Northern blots. Immunohistochemistry and Western blots of extracts showed COMP to be present in all regions of digital flexor tendons. Equine tendon COMP was purified by ion exchange chromatography and gel filtration and used in a heterologous inhibition ELISA to quantify COMP in equine digital flexor tendons at different ages, and in other tendons and ligaments. Mean COMP levels in digital flexor tendon were approximately 2-5mg/g wet weight, but they showed a large variation. Levels were low in neonatal tendon but rose rapidly during growth, with the metacarpal (tensional) superficial digital flexor tendon having the highest levels (approximately 10mg/g wet weight). Levels subsequently declined in this region, while in areas which experience a variable amount of compression, levels increased less but then remained constant. Extensor tendons and collateral ligaments, which experience less loading in vivo, had levels similar to those in neonatal tendon. COMP was identified in scarred skin and granulation tissue but not in normal skin, chronic fibrosis, or a fibrosarcomatous skin growth. A unilateral non-weight-bearing growing animal contained three to six times more COMP in the weight-bearing digital flexor tendons compared to the paralyzed limb, while the extensor tendons had similar amounts in both limbs. With the recent discovery of a COMP gene mutation causing pseudoachondroplasia (Hecht et al., 1995), in which lax tendons and ligaments are a feature, the present data suggest that COMP is synthesized in response to, and is necessary for tendon to resist, load.

Overexpression of glutathione S-transferase/glutathione peroxidase enhances the growth of transgenic tobacco seedlings during stress

Transgenic tobacco seedlings that overexpress a cDNA encoding an enzyme with both glutathione S-transferase (GST) and glutathione peroxidase (GPX) activity had GST- and GPX-specific activities approximately twofold higher than wild-type seedlings. These GST/GPX overexpressing seedlings grew significantly faster than control seedlings when exposed to chilling or salt stress. During chilling stress, levels of oxidized glutathione (GSSG) were significantly higher in transgenic seedlings than in wild-types. Growth of wild-type seedlings was accelerated by treatment with GSSG, while treatment with reduced glutathione or other sulfhydryl-reducing agents inhibited growth. Therefore, overexpression of GST/GPX can stimulate seedling growth under chilling and salt stress, and this effect could be caused by oxidation of the glutathione pool.

Ultrasonography of the equine triceps muscle before and after general anaesthesia and in post anaesthetic myopathy

The ultrasonographic appearance of the equine triceps muscle of clinically normal horses, before and after general anaesthesia, was investigated and compared with 5 cases of post anaesthetic myopathy. The triceps muscle areas were examined bilaterally using a 7.5 MHz linear array probe in 2 different planes, with each limb both weightbearing and nonweightbearing. The triceps muscles of 4 unanaesthetised horses were scanned twice, 24 h apart. Six horses underwent general anaesthesia and were scanned pre-anaesthesia and at 1 and 24 h intervals after recovery. Blood samples were obtained in the unanaesthetised group at each scan time and, in the anaesthetised group, pre-anaesthesia and at 10 min, 5 and 24 h after recovery. Creatine kinase (CK) and aspartate aminotransferase (AST) concentrations were measured. Anaesthetic details and recovery were related to the ultrasonographic and muscle enzyme findings. Five horses with post anaesthetic myopathy were scanned at intervals after the onset of clinical signs. In normal horses, the triceps muscle appeared ultrasonographically as echoic striations separated by anechoic areas. The fascia dividing muscle bellies was visible as an echoic line. Ultrasonographs obtained with the limb nonweightbearing had no change or a slight overall increase in echogenicity. The scans of control unanaesthetised horses were unchanged on successive days. All anaesthetised horses had uncomplicated anaesthesia and recoveries and did not exhibit any clinical signs of post anaesthetic myopathy. Elevated CK and AST values were found up to 342 and 195%, respectively, of the pre-anaesthetic values but no significant alterations in the ultrasonographic appearance of the muscles were detected. Clinical cases of post anaesthetic myopathy had disruption of the normal ultrasonographic pattern. There was an overall increase in echogenicity with a loss of the normal striated pattern. In 3 cases, there was localised increased echogenicity within the muscle. One of these horses was humanely destroyed for other reasons and histological examination of the affected muscle revealed a necrotic area correlating with the hyperechoic region. Two horses had bilateral involvement of the triceps musculature. Four horses recovered clinically from the myopathy and the ultrasonographic appearance returned to normal except in 1 horse where focal hyperechoic regions remained 10 weeks after the onset of the clinical signs.

A novel role for the integrin-binding III-10 module in fibronectin matrix assembly

Fibronectin matrix assembly is a cell-dependent process which is upregulated in tissues at various times during development and wound repair to support the functions of cell adhesion, migration, and differentiation. Previous studies have demonstrated that the alpha 5 beta 1 integrin and fibronectin's amino terminus and III-1 module are important in fibronectin polymerization. We have recently shown that fibronectin's III-1 module contains a conformationally sensitive binding site for fibronectin's amino terminus (Hocking, D.C., J. Sottile, and P.J. McKeown-Longo. 1994. J. Biol. Chem. 269: 19183-19191). The present study was undertaken to define the relationship between the alpha 5 beta 1 integrin and fibronectin polymerization. Solid phase binding assays using recombinant III-10 and III-1 modules of human plasma fibronectin indicated that the III-10 module contains a conformation-dependent binding site for the III-1 module of fibronectin. Unfolded III-10 could support the formation of a ternary complex containing both III-1 and the amino-terminal 70-kD fragment, suggesting that the III-1 module can support the simultaneous binding of III-10 and 70 kD. Both unfolded III-10 and unfolded III-1 could support fibronectin binding, but only III-10 could promote the formation of disulfide-bonded multimers of fibronectin in the absence of cells. III-10-dependent multimer formation was inhibited by both the anti-III-1 monoclonal antibody, 9D2, and amino-terminal fragments of fibronectin. A fragment of III-10, termed III-10/A, was able to block matrix assembly in fibroblast monolayers. Similar results were obtained using the III-10A/RGE fragment, in which the RGD site had been mutated to RGE, indicating that III-I0/A was blocking matrix assembly by a mechanism distinct from disruption of integrin binding. Texas red-conjugated recombinant III-1,2 localized to beta 1-containing sites of focal adhesions on cells plated on fibronectin or the III-9,10 modules of fibronectin. Monoclonal antibodies against the III-1 or the III-9,10 modules of fibronectin blocked binding of III-1,2 to cells without disrupting focal adhesions. These data suggest that a role of the alpha 5 beta 1 integrin in matrix assembly is to regulate a series of sequential self-interactions which result in the polymerization of fibronectin.

Relationships between polymorphism for mitochondrial deoxyribonucleic acid and yield traits of Holstein cows

Two independent data files from the breeding herd of Iowa State University and six North Carolina herds were used to examine relationships between yield traits and mtDNA polymorphism. Maternal lineages were established by tracing ancestry of cows to founder females in the herd book of the Holstein Association. Data from Iowa State University were 1476 records from 602 cows from 29 maternal lineages. The nucleotides of mtDNA encoding rRNA were sequenced. Eleven sites of polymorphism were found. An animal model for gene substitution was used to examine the relationship between sequence differences and yield traits. Traits analyzed were mature equivalent yield of milk, fat, SNF, and milk energy as well as concentrations of fat, SNF, and milk energy. Effects of sequence differences were significant for most traits. Sequence information from the D-loop was available for 12 lineages from North Carolina. The effect of polymorphism at 4 sites was examined using 1472 records from 668 cows. Traits measured were the same, except that protein replaced SNF. No significant relationships existed between any of the traits and D-loop polymorphism, but results suggested that an association might exist between polymorphism and concentrations of milk yield, fat percentage, and energy. Whenever a significant relationship was detected, the effect of mutation (rare genotype) was detrimental.