Ureteroileal anastomosis stricture after urinary diversions performed by open, laparoscopic and robotic approaches. Incidence and management in a tertiary care center.

INTRODUCTION: Ureteroileal anastomosis stricture is a frequent complication after radical cystectomy and ileal conduit or orthotopic neobladder formation. We analyze their incidence based on the technique for urinary diversion and on the surgical approach (open, laparoscopic or robot-assisted). Stricture management is described, along with surgical outcomes. MATERIAL AND METHODS: Descriptive retrospective study over 6 years in patients who underwent urinary diversion using ileum (ileal conduit or orthotopic neobladder). Demographic data, comorbidities, surgical approach, complications, and outcomes were collected. Minimum follow-up of 1 year. Comparison between groups using Chi-square test for dichotomous variables. Quantitative variables were compared using the Student's t-test for independent groups or Mann-Whitney test. Statistical significance if P < .05. RESULTS: The study included 182 patients (84% males and 16% females). Mean age 68 years. Cystectomy approach: laparoscopic (67/37%), robot-assisted (63/35%), open (43/24%). Urinary diversion: ileal conduit (138/76%) and orthotopic ileal neobladder (44/24%). Uretericre implantation technique: Bricker (108/59%) and Wallace (47/26%). Ureteroileal anastomosis strictures (50/27%): bilateral (26), left (16) and right (8). Strictures according to cystectomy approach: laparoscopic (23/46%), robot-assisted (16/32%), open (9/18%). Treatment of strictures (33/18%): ureteric reimplantation (13), indwelling nephrostomy (13), endoscopic dilatation (4), nephroureterectomy (2), endoureterotomy (1). Ureteroileal reimplantation approach: laparoscopic (5/38%), robot-assisted (6/46%), open (2/15%). Outcomes after reimplantation: restenosis (0/0%), reintervention (3/23%), contralateral ureteroileal stricture (1/8%). CONCLUSION: Surgical approach in cystectomy does not influence future development of ureteroileal strictures. Laparoscopic and robot-assisted ureteroileal reimplantation achieves high success rates.

Ureteroileal anastomosis stricture after urinary diversions performed by open, laparoscopic and robotic approaches. Incidence and management in a tertiary care center. / Estenosis de la anastomosis ureteroileal en derivaciones urinarias realizadas mediante abordaje abierto, laparoscópico y robótico. Incidencia y manejo en un centro de tercer nivel.

INTRODUCTION: Ureteroileal anastomosis stricture is a frequent complication after radical cystectomy and ileal conduit or orthotopic neobladder formation. We analyze their incidence based on the technique for urinary diversion and on the surgical approach (open, laparoscopic or robot-assisted). Stricture management is described, along with surgical outcomes. MATERIAL AND METHODS: Descriptive retrospective study over 6 years in patients who underwent urinary diversion using ileum (ileal conduit or orthotopic neobladder). Demographic data, comorbidities, surgical approach, complications, and outcomes were collected. Minimum follow-up of 1 year. Comparison between groups using Chi-square test for dichotomous variables. Quantitative variables were compared using the Student's t test for independent groups or Mann-Whitney test. Statistical significance if P<.05. RESULTS: The study included 182 patients (84% males and 16% females). Mean age 68 years. Cystectomy approach: laparoscopic (67/37%), robot-assisted (63/35%), open (43/24%). Urinary diversion: ileal conduit (138/76%) and orthotopic ileal neobladder (44/24%). Ureteric reimplantation technique: Bricker (108/59%) and Wallace (47/26%). Ureteroileal anastomosis strictures (50/27%): bilateral (26), left (16) and right (8). Strictures according to cystectomy approach: laparoscopic (23/46%), robot-assisted (16/32%), open (9/18%). Treatment of strictures (33/18%): ureteric reimplantation (13), indwelling nephrostomy (13), endoscopic dilatation (4), nephroureterectomy (2), endoureterotomy (1). Ureteroileal reimplantation approach: laparoscopic (5/38%), robot-assisted (6/46%), open (2/15%). Outcomes after reimplantation: restenosis (0/0%), reintervention (3/23%), contralateral ureteroileal stricture (1/8%). CONCLUSION: Surgical approach in cystectomy does not influence future development of ureteroileal strictures. Laparoscopic and robot-assisted ureteroileal reimplantation achieves high success rates.

Activity and short-term outcomes of kidney transplantation during the COVID-19 pandemic. / Actividad y resultados a corto plazo del trasplante renal durante la pandemia COVID-19.

INTRODUCTION: During the COVID-19 pandemic, the national transplant activity has been reduced due to the overload of the health system and concern for patient safety in this situation. The aim of our work is to expose the activity of kidney transplantation in Cantabria during the state of alarm, as well as to assess the safety of the transplantation program. MATERIAL AND METHODS: Retrospective study of kidney transplants performed in our Center from the beginning of the state of alarm until the beginning of the lockdown easing in Cantabria. Descriptive analysis of the demographic data of recipients and their donors, intraoperative data and postoperative outcomes. Comparative analysis with the data of the same period in 2017-2019, by means of the χ2 for categorical variables, Student's T and Mann-Whitney U tests in case of quantitative variables of normal and non-normal distribution, respectively. RESULTS: Fifteen kidney transplants were performed in the period described. Delayed renal function (DRF) was seen in 7.5% of patients, and 26.6% showed data of acute rejection; no patient presented COVID-19 disease. Comparative analysis showed a remarkable increase in the number of transplants in comparison with previous periods (15 vs 5.6), at the expense of donors from outside Cantabria (93.3%). We found no statistically significant differences in terms of cold ischemia time (p=0.77), DRF (p=0.73), need for dialysis (p=0.54), or appearance of post-surgical complications (p=0.61). CONCLUSIONS: The evolution of the pandemic in our region, and the adoption of strict protective measures has allowed the early and safe resumption of the renal transplantation program, increasing the number of transplants performed compared to previous years and maintaining comparable early post-operative results.

Percutaneous radiofrequency for the treatment of small renal masses: Analysis of outcomes and complications after 10 years of experience. / Radiofrecuencia percutánea en el tratamiento de masas renales pequeñas: análisis de resultados y complicaciones tras diez años de experiencia.

INTRODUCTION AND OBJECTIVE: The management of renal tumors ≤ 4 cm in elderly population or patients with comorbidities is a challenge, for which ablative therapies are an interesting alternative. The objective is to evaluate in our center the role of percutaneous radiofrequency in the treatment of small renal masses, the associated complications and the results obtained. MATERIAL AND METHODS: Retrospective evaluation of the radiofrequency treatments carried out between April 2010 and April 2020 in our center. Demographic data, associated comorbidities, tumor characteristics, complications and oncological and functional outcomes were reviewed. RESULTS: Fifty-seven tumors were treated in 53 patients. Mean follow-up of 48.2 months. The percentage of complete ablations obtained was of 89.5%. There were 19.3% of complications. According to Clavien-Dindo and SIR classification systems, 3.5% and 5.3% were major complications. A statistically significant association was found between the initial result of ablation and age (p = 0.047), RENAL-m (p = 0.044), the presence of cystic component (p = 0.049) and tumor size (p = 0.01). The cut-off point for size was established at 25 mm (p = 0.012). In multivariate analysis, only size remained as a predictor of initial ablation result (p = 0.01; OR 1.183; CI 95% 1.041-1.345). Cancer-specific survival and 5-year recurrence-free survival were 98.1% and 89.5%, respectively. A mean decrease of MDRD-4 of 6.59 mL/min (p = 0.005) was observed in the first six months after RFA. CONCLUSIONS: Given the excellent oncological and functional results demonstrated, ultrasound-guided percutaneous radiofrequency ablation is an effective and safe treatment for small renal masses in selected patients.

Therapeutic choices in patients with Ph-positive CML living in Mexico in the tyrosine kinase inhibitor era: SCT or TKIs?

A total of 72 patients with Ph-positive CML in first chronic phase were followed during a 6-year period in two different institutions in México. Among them, 22 were given a reduced-intensity allogeneic SCT, whereas 50 were given a tyrosine kinase inhibitor (TKI), mainly imatinib mesylate. The 6-year overall survival (OS) after the therapeutic intervention for patients allografted or given a TKI was 77 and 84%, respectively (P, NS); the median OS for both groups has not been reached, being above 90 and 71 months, respectively (P, NS). The freedom from progression to blast or accelerated phases was also similar for both groups, as well as the overall OS after diagnosis. Most patients allografted (91%) chose this treatment because they were unable to afford continuing treatment with the TKI, whereas most treated with the TKI (84%) were given the treatment without charge, through institutions able to pay for their treatment. The median cost of each nonmyeloablative allograft was US$18,000, an amount that is enough to cover 180 days of treatment with imatinib (400 mg per day) in México. Cost considerations favor allogeneic SCT as a 'once only' procedure whereas lifelong treatment with an expensive drug represents an excessive burden on resources.

Estenosis de la anastomosis ureteroileal en derivaciones urinarias realizadas mediante abordaje abierto, laparoscópico y robótico. Incidencia y manejo en un centro de tercer nivel / Ureteroileal anastomosis stricture after urinary diversions performed by open, laparoscopic and robotic approaches. Incidence and management in a tertiary care center

Introducción Las estenosis de anastomosis ureteroileal son complicaciones frecuentes en conductos ileales y neovejigas ortotópicas. Analizamos su incidencia en función del tipo de derivación urinaria y del abordaje quirúrgico (abierto, laparoscópico o robótico). Describimos su manejo y los resultados obtenidos.Material y métodos Estudio retrospectivo descriptivo durante 6 años en pacientes con derivación urinaria empleando íleon (conducto ileal o neovejiga ileal). Se recogen datos demográficos, comorbilidades, datos quirúrgicos (abordaje, complicaciones) y resultados. Seguimiento mínimo de un año. Comparación entre grupos, mediante test de la chi al cuadrado en variables dicotómicas. Variables cuantitativas comparadas empleando la prueba de la t Student para grupos independientes o la prueba de Mann-Whitney. Consideramos significación estadística p<0,05.Resultados Incluimos a 182 pacientes (84% varones y 16% mujeres). Edad media 68 años. Abordaje de cistectomía: laparoscópica (67/37%), robótica (63/35%), abierta (43/24%). Tipo de derivación: conducto ileal (138/76%) y neovejiga ileal ortotópica (44/24%). Tipo de reimplante: Bricker (108/59%) y Wallace (47/26%). Estenosis de anastomosis ureteroileal (50/27%): bilateral (26), izquierda (16) y derecha (8). Estenosis según abordaje de cistectomía: laparoscópica (23/46%), robótica (16/32%), abierta (9/18%). Tratamiento de estenosis (33/18%): reimplante ureteroileal (13), nefrostomía permanente (13), dilatación endoscópica (4), nefroureterectomía (2), endoureterotomía (1). Abordaje del reimplante: laparoscópico (5/38%), robótico (6/46%) y abierto (2/15%). Resultados tras reimplantes: reestenosis (0/0%), reintervención (3/23%), estenosis ureteroileal contralateral posterior (1/8%).ConclusiónEl tipo de abordaje empleado en la cistectomía no parece influir en la aparición de estenosis ureteroileales. Abordajes laparoscópicos y robóticos permiten su reparación con resultados

Introduction Ureteroileal anastomosis stricture is a frequent complication after radical cystectomy and ileal conduit or orthotopic neobladder formation. We analyze their incidence based on the technique for urinary diversion and on the surgical approach (open, laparoscopic or robot-assisted). Stricture management is described, along with surgical outcomes.Material and methodsDescriptive retrospective study over 6 years in patients who underwent urinary diversion using ileum (ileal conduit or orthotopic neobladder). Demographic data, comorbidities, surgical approach, complications, and outcomes were collected. Minimum follow-up of 1 year. Comparison between groups using Chi-square test for dichotomous variables. Quantitative variables were compared using the Student's t test for independent groups or Mann-Whitney test. Statistical significance if P<.05.Results The study included 182 patients (84% males and 16% females). Mean age 68 years. Cystectomy approach: laparoscopic (67/37%), robot-assisted (63/35%), open (43/24%). Urinary diversion: ileal conduit (138/76%) and orthotopic ileal neobladder (44/24%). Ureteric reimplantation technique: Bricker (108/59%) and Wallace (47/26%). Ureteroileal anastomosis strictures (50/27%): bilateral (26), left (16) and right (8). Strictures according to cystectomy approach: laparoscopic (23/46%), robot-assisted (16/32%), open (9/18%). Treatment of strictures (33/18%): ureteric reimplantation (13), indwelling nephrostomy (13), endoscopic dilatation (4), nephroureterectomy (2), endoureterotomy (1). Ureteroileal reimplantation approach: laparoscopic (5/38%), robot-assisted (6/46%), open (2/15%). Outcomes after reimplantation: restenosis (0/0%), reintervention (3/23%), contralateral ureteroileal stricture (1/8%).Conclusion Surgical approach in cystectomy does not influence future development of ureteroileal strictures. Laparoscopic and robot-assisted ureteroileal reimplantation achieves high success rates (AU)

Actividad y resultados a corto plazo del trasplante renal durante la pandemia COVID-19 / Activity and short-term outcomes of kidney transplantation during the COVID-19 pandemic

INTRODUCCIÓN: Durante la pandemia COVID-19, la actividad nacional de trasplante se ha visto reducida por la sobrecarga del sistema sanitario y la preocupación por la seguridad de los pacientes en esta situación. El objetivo de nuestro trabajo es exponer la actividad de trasplante renal en Cantabria durante el estado de alarma, así como valorar la seguridad del programa de trasplante. MATERIAL Y MÉTODOS: Estudio retrospectivo de los trasplantes renales realizados en nuestro Centro desde el inicio del estado de alarma hasta el inicio del desconfinamiento en Cantabria. Análisis descriptivo de los datos demográficos de receptores y sus donantes, datos intraoperatorios y resultados postoperatorios. Análisis comparativo con los datos del mismo periodo de 2017-2019, mediante los estadísticos χ2 para variables categóricas, T-Student y U de Mann-Whitney en caso de variables cuantitativas de distribución normal y no normal, respectivamente. RESULTADOS: Se realizaron 15 trasplantes renales en el periodo descrito. El 7,5% de pacientes presentaron función renal retrasada (FRR); el 26,6% mostró datos de rechazo agudo; ningún paciente presentó enfermedad por COVID-19. En el análisis comparativo, es llamativo el aumento del número de trasplantes frente a periodos anteriores (15 vs. 5,6), a expensas de donantes de fuera de Cantabria (93,3%). No encontramos diferencias estadísticamente significativas en cuanto a tiempo de isquemia fría (p = 0,77), FRR (p = 0,73), necesidad de diálisis (p = 0,54), o aparición de complicaciones posquirúrgicas (p = 0,61). CONCLUSIONES: La evolución de la pandemia en nuestra región y la adopción de medidas de protección rigurosas han permitido reiniciar el programa de trasplante renal de una forma temprana y segura, aumentando el número de trasplantes realizados frente a años anteriores y manteniendo unos resultados postoperatorios tempranos comparables

INTRODUCTION: During the COVID-19 pandemic, the national transplant activity has been reduced due to the overload of the health system and concern for patient safety in this situation. The aim of our work is to expose the activity of kidney transplantation in Cantabria during the state of alarm, as well as to assess the safety of the transplantation program. MATERIAL AND METHODS: Retrospective study of kidney transplants performed in our Center from the beginning of the state of alarm until the beginning of the lockdown easing in Cantabria. Descriptive analysis of the demographic data of recipients and their donors, intraoperative data and postoperative outcomes. Comparative analysis with the data of the same period in 2017-2019, by means of the χ2 for categorical variables, Student's T and Mann-Whitney U tests in case of quantitative variables of normal and non-normal distribution, respectively. RESULTS: Fifteen kidney transplants were performed in the period described. Delayed renal function (DRF) was seen in 7.5% of patients, and 26.6% showed data of acute rejection; no patient presented COVID-19 disease. Comparative analysis showed a remarkable increase in the number of transplants in comparison with previous periods (15 vs 5.6), at the expense of donors from outside Cantabria (93.3%). We found no statistically significant differences in terms of cold ischemia time (p = 0.77), DRF (p = 0.73), need for dialysis (p = 0.54), or appearance of post-surgical complications (p = 0.61). CONCLUSIONS: The evolution of the pandemic in our region, and the adoption of strict protective measures has allowed the early and safe resumption of the renal transplantation program, increasing the number of transplants performed compared to previous years and maintaining comparable early post-operative results

Studies on the dissemination of Salmonella in nine broiler-chicken flocks.

The salmonella status of nine different broiler-chicken flocks was studied from the day before the chickens were placed in the house until their sixth week of age. The presence of salmonella serotypes in dust, litter, feces, water, and feed was investigated. Dust from different sites was sampled and appeared to be contaminated with salmonellae even after six of the nine houses were disinfected. Defects in the cleaning and disinfection of air inlets and fans seemed to be an important factor for the recontamination of the house. Chickens were often contaminated at the hatchery, and in two houses the percentage of contamination had increased to as much as 82 7% and 88 8% at six weeks of age. Swabbing of intact and fresh feces appeared to be a more reliable technique than culturing the litter for evaluating the shedder state of the flock, and it appeared also to be more rapid and simple than the collection of cloacal swabs.

Bioavailability of chloramphenicol in cattle: variation with the number of injection sites and the concentration of the pharmaceutical preparation.

A bioavailability study of three commercial chloramphenicol preparations was carried out in cattle in order to determine the influence of the number of muscular injection sites and the concentration of the product on the level of chloramphenicol serum concentration. Results show that chloramphenicol should be injected at the dose of 22 mg/kg at multiple injection sites to reach 5 mug/mL of serum which is considered to be the minimal inhibitory concentration.

[Isolation of infectious bovine rhinotracheitis virus from the tarsal joint of a bull (author's transl)]. / Isolement du virus de la rhino-trachéite infectieuse bovine à partir du liquide synovial du tarse d'un taureau.

Isolation of infectious bovine rhinotracheitis virus from the tarsal joint of a bullInfectious bovine rhinotracheitis virus was isolated from the right tarsal joint of a bull who was showing signs of a systemic viral infection. The clinical signs manifested by 16 bulls of this herd are described, the laboratory methods used are listed and the results are analysed and discussed.

[Dermatophilus congolensis infection in a dairy cow in Quebec (author's transl)]. / Histoire de cas: infection à Dermatophilus congolensis chez une vache laitière, au Québec.

Dermatophilus congolensis infection in a dairy cow in QuebecA case of infection by Dermatophilus congonlensis is described for the first time in the Province of Quebec, in a dairy cow. Dermatophilosis was diagnosed in the area of Saint-Hyacinthe in October 1978. It was not possible to find the source of the infection. The isolation of the microorganism was successful and the three techniques used are described. The death of the animal was attributed to complications following invasion by a secondary pathogen. All the other animals in the herd were free from clinical signs of infection. Moreover, no other case of infection by D. congolensis was found in other animal species or humans in the area.

Actividad y resultados a corto plazo del trasplante renal durante la pandemia COVID-19 / Activity and short-term outcomes of kidney transplantation during the COVID-19 pandemic

INTRODUCCIÓN: Durante la pandemia COVID-19, la actividad nacional de trasplante se ha visto reducida por la sobrecarga del sistema sanitario y la preocupación por la seguridad de los pacientes en esta situación. El objetivo de nuestro trabajo es exponer la actividad de trasplante renal en Cantabria durante el estado de alarma, así como valorar la seguridad del programa de trasplante. MATERIAL Y MÉTODOS: Estudio retrospectivo de los trasplantes renales realizados en nuestro Centro desde el inicio del estado de alarma hasta el inicio del desconfinamiento en Cantabria. Análisis descriptivo de los datos demográficos de receptores y sus donantes, datos intraoperatorios y resultados postoperatorios. Análisis comparativo con los datos del mismo periodo de 2017-2019, mediante los estadísticos χ2 para variables categóricas, T-Student y U de Mann-Whitney en caso de variables cuantitativas de distribución normal y no normal, respectivamente. RESULTADOS: Se realizaron 15 trasplantes renales en el periodo descrito. El 7,5% de pacientes presentaron función renal retrasada (FRR); el 26,6% mostró datos de rechazo agudo; ningún paciente presentó enfermedad por COVID-19. En el análisis comparativo, es llamativo el aumento del número de trasplantes frente a periodos anteriores (15 vs. 5,6), a expensas de donantes de fuera de Cantabria (93,3%). No encontramos diferencias estadísticamente significativas en cuanto a tiempo de isquemia fría (p = 0,77), FRR (p = 0,73), necesidad de diálisis (p = 0,54), o aparición de complicaciones posquirúrgicas (p = 0,61). CONCLUSIONES: La evolución de la pandemia en nuestra región y la adopción de medidas de protección rigurosas han permitido reiniciar el programa de trasplante renal de una forma temprana y segura, aumentando el número de trasplantes realizados frente a años anteriores y manteniendo unos resultados postoperatorios tempranos comparables

INTRODUCTION: During the COVID-19 pandemic, the national transplant activity has been reduced due to the overload of the health system and concern for patient safety in this situation. The aim of our work is to expose the activity of kidney transplantation in Cantabria during the state of alarm, as well as to assess the safety of the transplantation program. MATERIAL AND METHODS: Retrospective study of kidney transplants performed in our Center from the beginning of the state of alarm until the beginning of the lockdown easing in Cantabria. Descriptive analysis of the demographic data of recipients and their donors, intraoperative data and postoperative outcomes. Comparative analysis with the data of the same period in 2017-2019, by means of the χ2 for categorical variables, Student's T and Mann-Whitney U tests in case of quantitative variables of normal and non-normal distribution, respectively. RESULTS: Fifteen kidney transplants were performed in the period described. Delayed renal function (DRF) was seen in 7.5% of patients, and 26.6% showed data of acute rejection; no patient presented COVID-19 disease. Comparative analysis showed a remarkable increase in the number of transplants in comparison with previous periods (15 vs 5.6), at the expense of donors from outside Cantabria (93.3%). We found no statistically significant differences in terms of cold ischemia time (p = 0.77), DRF (p = 0.73), need for dialysis (p = 0.54), or appearance of post-surgical complications (p = 0.61). CONCLUSIONS: The evolution of the pandemic in our region, and the adoption of strict protective measures has allowed the early and safe resumption of the renal transplantation program, increasing the number of transplants performed compared to previous years and maintaining comparable early post-operative results

[Evaluation of 4 enrichment media f the demonstration of avian Salmonellae]. / Evaluation de quatre milieux d'enrichissement pour la mise en évidence des salmonelles aviaires.

During the course of one natural and two experimental infections with Salmonella the authors evaluated four different enrichment media for the isolation and growth of these organisms. The final results indicate that the utilisation of only one medium is not sufficient. They suggest the addition of M.M. medium to the Sodium Tetrathionate and Selenite broth. The M.S. medium proved to be too inhibiting.

[Aortic prosthesis, long-term results and evolution]. / Prótesis aórtica, Resultado y evolución a largo plazo

The results and evolution of 126 aortic prosthesis implanted from 1964 to 1971 were reported. The results are appraised according to the criteria of the NYHA. The hospital mortality in the first five years was 40%; in those operated on in the following 3 it fell to 21% and finally those treated in the last 2 years had 16%. The delayed mortality was 19%. Depending on the type of valvular lesion, the stenosis have the highest mortality (50%). The group II and II of the NYHA had less mortality. In the evolution of the survivors at ten years, the incidence of actual survivors shows that after the first two years of prosthetic change, the survival rate tends to stabilize staying at 77% at the end of 10 years; of which 75% evolve well and 17% badly. A separate analysis was made of the factors which modify the results and evolution such as calcifications, associated mitraltricuspid lesions, and myocardial damage. The most frequent complications were embolisms 14%, prosthetic dysfunction 12.8%, endocarditis 3.8%, and hemolysis 2.5%.

[Necrotic enteritis in broilers. II. Characteristics of the strains of Clostridium perfringens isolated]. / Entérite nécrotique chez le poulet de gril. II. Caractères des souches de Clostridium perfringens isolées

A Gram positive bacillus, strictly anaerobic, was isolated from the viscera of all diseased birds showing lesions of necrotic enteritis. Its morphology and biochemical reactions, the presence of alpha and thêta hemolysins and the production of a lecithinase-C in vitro, all these characteristics indicated a similarity to those belonging to the group of Clostridium perfringens. The two hemolysins were neutralized in vitro only by the antitoxin A. Broiler chickens injected I.V. with a Viande-Foie (VF) broth culture of Clostridium perfringens together with the antitoxin A survived, whereas those receiving antitoxin C died. These results seem to indicate that this organism belongs to the type A. This bacillus was sensitive to a great variety of antibiotics, except neomycin.

[Residual estimates of international emigration according to mother tongue, Quebec, 1971-1976]. / Estimations residuelles de l'emigration internationale selon la langue maternelle, Quebec, 1971-1976

PIP: The authors examine the validity of data from the Canadian census for estimating international emigration, with particular reference to estimates by language group. Using the method of residual estimation on official Canadian data, they calculate a negative estimate of -35,848 Anglophones emigrating from Quebec over the period 1971-1976. They conclude that this estimate must be an error and suggest that it is caused by changes in mother tongue between censuses. Methods of correcting the problem are proposed. Consideration is also given to the general problem of under-enumeration in Canadian censuses and the effect this would have on residual estimations.^ieng