First Reported Case of Malignant Ectomesenchymoma with p.Leu122Arg Mutation in MYOD1 Gene: Extensive Intra- and Extracranial Tumor in a 15-Year-Old Female

BACKGROUND

Ectomesenchymomas (EMs) are extremely rare neoplasms composed of malignant mesenchymal components and neuroectodermal derivatives. They are described in a wide variety of locations, with the head and neck region being one of the most frequently involved areas. EMs are usually managed as high-risk rhabdomyosarcomas and have similar outcomes.

METHODS

We present the case of a 15-year-old female with an EM that arose in the parapharyngeal space and extended into the intracranial space.

RESULTS

Histologically, the tumor presented an embryonal rhabdomyosarcomatous mesenchymal component and the neuroectodermal component was constituted by isolated ganglion cells. Next-generation sequencing (NGS) revealed a p.Leu122Arg (c.365 T > G) mutation in the MYOD1 gene, a p.Ala34Gly mutation in the CDKN2A gene, and CDK4 gene amplification. The patient was treated with chemotherapy. She died 17 months after the debut of symptoms.

CONCLUSION(S)

To our knowledge, this is the first reported case in English literature of an EM with this MYOD1 mutation. We suggest combining PI3K/ATK pathway inhibitors in these cases. NGS should be performed in EMs cases to detect mutations with potential treatment options.

A phase I/II dose-escalation multi-center study to evaluate the safety of infusion of natural killer cells or memory T cells as adoptive therapy in coronavirus pneumonia and/or lymphopenia: RELEASE study protocol

BACKGROUND

Moderate/severe cases of COVID-19 present a dysregulated immune system with T cell lymphopenia and a hyper-inflammatory state. This is a study protocol of an open-label, multi-center, double-arm, randomized, dose-finding phase I/II clinical trial to evaluate the safety, tolerability, alloreactivity, and efficacy of the administration of allogeneic memory T cells and natural killer (NK) cells in COVID-19 patients with lymphopenia and/or pneumonia. The aim of the study is to determine the safety and the efficacy of the recommended phase 2 dose (RP2D) of this treatment for patients with moderate/severe COVID-19.

METHODS

In the phase I trial, 18 patients with COVID-19-related pneumonia and/or lymphopenia with no oxygen requirement or with an oxygen need of ≤ 2.5 liters per minute (lpm) in nasal cannula will be assigned to two arms, based on the biology of the donor and the patient. Treatment of arm A consists of the administration of escalating doses of memory T cells, plus standard of care (SoC). Treatment of arm B consists of the administration of escalating doses of NK cells, plus SoC. In the phase II trial, a total of 182 patients with COVID-19-related pneumonia and/or lymphopenia requiring or not oxygen supplementation but without mechanical ventilation will be allocated to arm A or B, considering HLA typing. Within each arm, they will be randomized in a 1:1 ratio. In arm A, patients will receive SoC or RP2D for memory T cells plus the SoC. In arm B, patients will receive SoC or RP2D for NK cells plus the SoC.

DISCUSSION

We hypothesized that SARS-CoV-2-specific memory T-lymphocytes obtained from convalescent donors recovered from COVID-19 can be used as a passive cell immunotherapy to treat pneumonia and lymphopenia in moderate/severe patients. The lymphopenia induced by COVID-19 constitutes a therapeutic window that may facilitate donor engraftment and viral protection until recovery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04578210 . First Posted : October 8, 2020.

Phase I dose-escalation single centre clinical trial to evaluate the safety of infusion of memory T cells as adoptive therapy in COVID-19 (RELEASE)

BACKGROUND

Effective treatments are still needed to reduce the severity of symptoms, time of hospitalization, and mortality of COVID-19. SARS-CoV-2 specific memory T-lymphocytes obtained from convalescent donors recovered can be used as passive cell immunotherapy.

METHODS

Between September and November 2020 a phase 1, dose-escalation, single centre clinical trial was conducted to evaluate the safety and feasibility of the infusion of CD45RA^- memory T cells containing SARS-CoV-2 specific T cells as adoptive cell therapy against moderate/severe cases of COVID-19. Nine participants with pneumonia and/or lymphopenia and with at least one human leukocyte antigen (HLA) match with the donor were infused. The first three subjects received the lowest dose (1 × 10⁵ cells/kg), the next three received the intermediate dose (5 × 10⁵ cells/kg) and the last three received the highest dose (1 × 10⁶ cells/kg) of CD45RA^- memory T cells. Clinicaltrials.gov registration: NCT04578210.

FINDINGS

All participants' clinical status measured by National Early Warning Score (NEWS) and 7-category point ordinal scales showed improvement six days after infusion. No serious adverse events were reported. Inflammatory parameters were stabilised post-infusion and the participants showed lymphocyte recovery two weeks after the procedure. Donor microchimerism was observed at least for three weeks after infusion in all patients.

INTERPRETATION

This study provides preliminary evidence supporting the idea that treatment of COVID-19 patients with moderate/severe symptoms using convalescent CD45RA^- memory T cells is feasible and safe.

FUNDING

Clinical Trial supported by Spanish Clinical Research Network PT17/0017/0013. Co-funded by European Regional Development Fund/European Social Fund. CRIS CANCER Foundation Grant to AP-M and Agencia Valenciana de Innovación Grant AVI-GVA COVID-19-68 to BS.

The paediatric cancer clinical research landscape in Spain: a 13-year multicentre experience of the new agents group of the Spanish Society of Paediatric Haematology and Oncology (SEHOP)

PURPOSE

Early phase trials are crucial in developing innovative effective agents for childhood malignancies. We report the activity in early phase paediatric oncology trials in Spain from its beginning to the present time and incorporate longitudinal data to evaluate the trends in trial characteristics and recruitment rates.

METHODS

Members of SEHOP were contacted to obtain information about the open trials at their institutions. The study period was split into two equal periods for analysis: 2007-2013 and 2014-2020.

RESULTS

Eighty-one trials and two molecular platforms have been initiated. The number of trials has increased over the time of the study for all tumour types, with a predominance of trials available for solid tumours (66%). The number of trials addressed to tumours harbouring specific molecular alterations has doubled during the second period. The proportion of industry-sponsored compared to academic trials has increased over the same years. A total of 565 children and adolescents were included, with an increasing trend over the study period. For international trials, the median time between the first country study approval and the Spanish competent authority approval was 2 months (IQR 0-6.5). Fourteen out of 81 trials were sponsored by Spanish academic institutions.

CONCLUSIONS

The number of available trials, and the number of participating patients, has increased in Spain from 2007. Studies focused on molecular-specific targets are now being implemented. Barriers to accessing new drugs for all ranges of age and cancer diseases remain. Additionally, opportunities to improve academic research are still required in Spain.

SARS-CoV-2-Specific Memory T Lymphocytes From COVID-19 Convalescent Donors: Identification, Biobanking, and Large-Scale Production for Adoptive Cell Therapy

Syndrome coronavirus 2 (SARS-CoV-2) pandemic is causing a second outbreak significantly delaying the hope for the virus’ complete eradication. In the absence of effective vaccines, we need effective treatments with low adverse effects that can treat hospitalized patients with COVID-19 disease. In this study, we determined the existence of SARS-CoV-2-specific T cells within CD45RA^– memory T cells in the blood of convalescent donors. Memory T cells can respond quickly to infection and provide long-term immune protection to reduce the severity of COVID-19 symptoms. Also, CD45RA^– memory T cells confer protection from other pathogens encountered by the donors throughout their life. It is of vital importance to resolve other secondary infections that usually develop in patients hospitalized with COVID-19. We found SARS-CoV-2-specific memory T cells in all of the CD45RA^– subsets (CD3⁺, CD4⁺, and CD8⁺) and in the central memory and effector memory subpopulations. The procedure for obtaining these cells is feasible, easy to implement for small-scale manufacture, quick and cost-effective, involves minimal manipulation, and has no GMP requirements. This biobank of specific SARS-CoV-2 memory T cells would be immediately available “off-the-shelf” to treat moderate/severe cases of COVID-19, thereby increasing the therapeutic options available for these patients.

Challenges in early phase clinical trials for childhood cancer during the COVID-19 pandemic: a report from the new agents group of the Spanish Society of Paediatric Haematology and Oncology (SEHOP)

PURPOSE

The COVID-19 pandemic has forced healthcare stakeholders towards challenging decisions. We analyse the impact of the pandemic on the conduct of phase I-II trials for paediatric cancer during the first month of state of alarm in Spain.

METHODS

A questionnaire was sent to all five ITCC-accredited Spanish Paediatric Oncology Early Phase Clinical Trial Units, including questions about impact on staff activities, recruitment, patient care, supply of investigational products, and legal aspects.

RESULTS

All units suffered personnel shortages and difficulties in enrolling patients, treatment continuity, or performing trial assessments. Monitoring activity was frequently postponed (73%), and 49% of on-going trials interrupted recruitment. Only two patients could be recruited during this period (75% reduction in the expected rate).

CONCLUSIONS

The COVID-19 crisis has significantly impacted clinical research practice and access to innovation for children with cancer. Structural and functional changes are under way to better cope with the expected future restrictions.

[An infant with intestinal pneumatosis and pneumoperitoneum: the difficult decision not to intervene]

Pneumoperitoneum in children may be due to causes that do not require urgent surgery (cardiopulmonary resuscitation manoeuvres, severe respiratory pathology or mechanical ventilation). Surgery in these cases could even worsen the prognosis. We present the case of a male infant, ex-preterm, with a history of necrotizing enterocolitis and ileal perforation at birth, requiring laparotomy and intestinal resection on two occasions and developing a secondary microcolon, due to disuse. At six months, after transitioning to full oral feeding, he presented abdominal distension with extensive intestinal pneumatosis and pneumoperitoneum on radiographs. His general appearance was good with normal intestinal transit and no peritonitis. The patient remained fasting with intravenous antibiotics, nasogastric decompression and parenteral nutrition. The evolution was favourable with oral feeding restarting on the seventh day of admission. The existence of pneumoperitoneum does not always require a laparotomy and global assessment of the patient by an interdisciplinary health team may avoid unnecessary aggressive treatments.

The role of CDKN2A/B deletions in pediatric acute lymphoblastic leukemia

The CDKN2A/B genes in the 9p21 chromosomal region are frequently involved in human cancer, including pediatric acute lymphoblastic leukemia (ALL). These genes encode 3 proteins that belong to the RB1 and TP53 pathways and act as tumor suppressors by regulating the G1/S checkpoint of the cell cycle. The prognostic value of deletions in the CDKN2A/B locus in ALL is controversial in part due to the limitations of the methodologies used. Further studies with advanced technologies are needed for elucidation. Future studies would also highlight whether CDK4/CDK6 selective inhibitors might be useful therapies for children with these genetic aberrations.

Identification of genetic variants in pharmacokinetic genes associated with Ewing Sarcoma treatment outcome

BACKGROUND

Despite the effectiveness of current treatment protocols for Ewing sarcoma (ES), many patients still experience relapse, and survival following recurrence is <15%. We aimed to identify genetic variants that predict treatment outcome in children diagnosed with ES.

PATIENTS AND METHODS

We carried out a pharmacogenetic study of 384 single-nucleotide polymorphisms (SNPs) in 24 key transport or metabolism genes relevant to drugs used to treat in pediatric patients (<30 years) with histologically confirmed ES. We studied the association of genotypes with tumor response and overall survival (OS) in a discovery cohort of 106 Spanish children, with replication in a second cohort of 389 pediatric patients from across Europe.

RESULTS

We identified associations with OS (P < 0.05) for three SNPs in the Spanish cohort that were replicated in the European cohort. The strongest association observed was with rs7190447, located in the ATP-binding cassette subfamily C member 6 (ABCC6) gene [discovery: hazard ratio (HR) = 14.30, 95% confidence interval (CI) = 1.53-134, P = 0.020; replication: HR = 9.28, 95% CI = 2.20-39.2, P = 0.0024] and its correlated SNP rs7192303, which was predicted to have a plausible regulatory function. We also replicated associations with rs4148737 in the ATP-binding cassette subfamily B member 1 (ABCB1) gene (discovery: HR = 2.96, 95% CI = 1.08-8.10, P = 0.034; replication: HR = 1.60, 95% CI = 1.05-2.44, P = 0.029), which we have previously found to be associated with poorer OS in pediatric osteosarcoma patients, and rs11188147 in cytochrome P450 family 2 subfamily C member 8 gene (CYP2C8) (discovery : HR = 2.49, 95% CI = 1.06-5.87, P = 0.037; replication: HR = 1.77, 95% CI = 1.06-2.96, P = 0.030), an enzyme involved in the oxidative metabolism of the ES chemotherapeutic agents cyclophosphamide and ifosfamide. None of the associations with tumor response were replicated.

CONCLUSION

Using an integrated pathway-based approach, we identified polymorphisms in ABCC6, ABCB1 and CYP2C8 associated with OS. These associations were replicated in a large independent cohort, highlighting the importance of pharmacokinetic genes as prognostic markers in ES.

Activated and expanded natural killer cells target osteosarcoma tumor initiating cells in an NKG2D-NKG2DL dependent manner

Current therapies fail to cure most metastatic or recurrent bone cancer. We explored the efficacy and the pathways involved in natural killer (NK) cells' elimination of osteosarcoma (OS) cells, including tumor initiating cells (TICs), which are responsible for chemotherapy resistance, recurrence, and metastasis. The expression of ligands for NK cell receptors was studied in primary OS cell lines by flow cytometry. In vitro cytotoxicity of activated and expanded NK (NKAE) cells against OS was tested, and the pathways involved explored by using specific antibody blockade. NKAE cells' ability to target OS TICs was analyzed by flow cytometry and sphere formation assays. Spironolactone (SPIR) was tested for its ability to increase OS cells' susceptibility to NK cell lysis in vitro and in vivo. We found OS cells were susceptible to NKAE cells' lysis both in vivo and in vitro, and this cytolytic activity relied on interaction between NKG2D receptor and NKG2D ligands (NKG2DL). SPIR increased OS cells' susceptibility to lysis by NKAE cells, and could shrink the OS TICs. Our results show NKAE cells target OS cells including the TICs compartment, supporting the use of NK-cell based immunotherapies for OS.

[Are we correctly treating pilonidal disease in children? therapeutic goals beyond preventing recurrence]

INTRODUCTION

We present a retrospective study of our paediatric patients affected by pilonidal disease over the last 5 years.

PATIENTS AND METHOD

In all cases a broad excision of the pilonidal tissue was made, without colour signing the different incision sites and primary closure of the defect with no drainage.

RESULTS

Using this technique we treated 20 adolescents (15 girls and 5 boys) of ages between 12 and 15 years (average age 13.3 years) and body mass index between 17 and 33 (mean BMI 26.4 kg/m2). Mean hospitalisation time was 1.45 days. Preoperative antibiotherapy with Amoxicillin-clavulanic was administered to 55% of patients and continued over the first postoperative week. We had four cases with recurrence of the disease (25%) (two of these with two recurrences), which we treated with three primary closures on the midline and three by flattening the cleft. In 2 cases with dehiscence of the wound we allowed treatment by secondary intention. No flaps or marsupialisation were attempted in any case. In all cases the result was aesthetically satisfactory, with maintenance of the intergluteal fold.

CONCLUSIONS

In our series we have succeeded in undertaking primary closure of the defect after pilonidal resection without any excessive tension. This treatment enables a rapid return to a normal routine. We considered it important to undertake surgery that maintained the intergluteal fold, especially in patients with a short-term evolution of the disease, reserving flattening the cleft, closure by secondary intention, or primary closure by inserting flaps only for cases of recurrent disease; those with long-term evolution; or patients with complex lesions prior to surgery. Nutritional support to reduce overweight is very important in many patients.

[Scarring after Mustarde otoplasty: importance of cures and post-operative follow-up of the patients]

INTRODUCTION

In the treatment protocol for patients with Mustardé otoplasties we use tennis head sweatbands for 2 months (to be worn all the time in the first month and only at night in the second month) to protect the correction obtained and to avoid traumatisms.

MATERIAL AND METHODS

We describe the cases of 3 patients who underwent Mustardé otoplasty and presented sloughs in the anterior edge of the antehelix that are secondary to the pressure of the compression bandage.

RESULTS

One patient operated for unilateral malformation suffered bilateral scars (in the operated ear and in the healthy one). This prove that the scars are secondary to the dressings not to surgery. In two patients the sloughs evolved into the formation of nodular hypertrophic scars, which were slowly corrected with silicone dressings and externally applied corticosteroids and moisturising creams in one patient and had to be resected in the other.

CONCLUSIONS

It is important to give a detailed explanation to the parents about the mission and characteristics of the sweatbands, and also about the need to frequently check their correct placing. This is to avoid a complication that, without spoiling the final result of the otoplasty, reduces patient satisfaction and extends the recovery period.

[Treatment of adolescent varicocele: is percutaneous embolization better?]

There are still doubts as to the most suitable criteria when considering surgery as the indication and optimal treatment for adolescent varicocele.

MATERIAL AND PATIENTS

We reviewed the hospital and primary health care histories of patients diagnosed by ultrasound for varicocele over the last 7 years. The data was taken from computerised clinical histories and hard copy back-up material stored and processed in computer format.

RESULTS

We studied 135 cases (mean age 12.8 years). These patients (125) were referred for scrotal swelling or as a result of chance detection, except for 10 patients who reported pain or scrotal asymmetry. Seventy-three underwent surgery and 62 continued as controls over the study period. The surgical indication was significant progressive asymmetry in testicular volume (28 children), high grade varicocele (41) as well as other reasons (4). We undertook percutaneous embolization in 44 patients (with a 66% relapse rate) and laparoscopic section of the spermatic cord with no arterial preservation in 29 (no relapses but 7 post-surgery hydroceles). No testicles were lost. At the end of the study 10 children continued as controls, 34 were discharged after recovery, 56 were referred to urology due to their age group, and 35 were lost to the study.

DISCUSSION

In the controversy over the treatment of varicocele our experience shows a high degree of relapses after embolization. Section of the spermatic vessels (including the artery) with no lymphatic preservation is highly effective but involves 27% post-op hydroceles, usually self-limiting (only one had later to undergo surgery), with no testicular atrophy or other complications.

CONCLUSIONS

We prefer complete laparoscopic section of the spermatic pedicle to embolization but it would be advisable to introduce modifications to avoid post-surgical hydrocele. Embolization must be reserved for patients with one testicle or with bilateral disease. Efforts must be made to communicate more effectively, in order to reduce the high drop-out rate.

Mobilisation of mesenchymal cells into blood in response to skeletal muscle injury

Mesenchymal cells recruited to damaged tissues must circulate through the bloodstream. The absolute numbers of circulating mesenchymal stem cells (cMSCs) in two different models of acute and chronic skeletal muscle injury were determined. cMSCs were present in significantly higher numbers in both models than in healthy controls. These results support the hypothesis that MSCs are mobilised into the bloodstream after skeletal muscle tissue damage. These two models (acute and chronic) would be of value in the search for molecular mediators of mobilisation of MSCs into the circulation.

An intra-thyroid thyroglossal duct cyst

Thyroglossal duct cysts can be found in several different locations, although intra-thyroid presentations are rare. We present the case of an 11-year-old patient with a visible neck mass on the right thyroid lobe. On sonogram, it was consistent with a unilocular cyst measuring 2 centimeters in diameter. The cyst did not take up the radioisotope during a gammagram. Fine needle aspiration cytology suggested a diagnosis of thyroglossal duct cyst. At surgery, we found that there were no lesion-dependent thyroglossal tracts; we therefore performed a simple enucleation of the cyst, sparing the rest of the gland. The pathologic examination confirmed that it was an intra-thyroid thyroglossal duct cyst. After 8 months of follow-up, the patient has remained without complications of any kind or recurrence. Only four prior cases of intra-thyroid thyroglossal cysts have been described in the pediatric population. Half of them presented with a typical thyroglossal tract crossing the hyoid and the other half presented an isolated cyst. It is highly unlikely that a cold, cystic, thyroid mass in a child is a thyroglossal duct cyst. Diagnosis is made on the basis of fine needle aspiration cytology and the lesion is treated surgically. A thyroglossal tract must be methodically sought out during intervention, although they frequently do not exist.

[Programmed surgery for acute appendicitis]

Non-complicated appendicitis surgery is still considered to be an emergency, although it has been observed that a reasonable therapeutic delay (up to 18 hours) does not imply a higher number of complications. In our department, surgery is programmed for those non-complicated appendicitis, thus avoiding duty staff (surgeons, anaesthesiologists, nurses, assistants) to operate during late night. Acute appendicitis records from august 2001 to december 2002 were reviewed. Collected data included: clinical findings, physical examination, ultrasound findings, surgical delay (recorded time from emergency attendance until the end of the surgery) and evolution. A total of 209 patiens (125 males and 84 females) underwent surgery. Mean age was 10.1 years (standard deviation 3.02). A non-complicated appendicitis group (NC) included 171 subjects while the complicated appendicitis group (C) included 38, assessed by means of clinical evaluation plus ultrasonography. Patients in NC group had programmed surgery, with up to 20-hour delay (mean of 7 hours 45 minutes). Mean admission time was 4.87 days with a percentage of infectious complications of 1.73%. Patients in group C underwent surgery as soon as possible. Mean admission time was 9.23 days (p < 0.0001) and percentage of infectious complications of 43.6%. There was no difference between those operated rapidly and those who were delayed. Patiens with non-complicated disease could undergo programmed surgery, without having a higher risk of complicated disease and without disturbing normal department activity.

[Ultrasonography for surgical pathology discrimination in acute abdominal pain. Prospective study]

Abdominal ultrasonographic study is a part of the acute abdominal pain diagnosis protocol in our hospital. As an internal quality assessment, we performed a six-month prospective study, including those patients who meet one of these requirements: 1st the reason for attendance being non-traumatic abdominal pain 2nd an abdominal ultrasonography achieved at the hospital. Collected data included: demographic characteristics, presenting sign and symptoms, test results, ultrasonography, final diagnosis and treatment. Children attended to the hospital were evaluated through clinical findings to verify concordance between clinical and ultrasound diagnosis, and patients who did not stay at the hospital had telephone follow-up in 2 weeks. A total of 136 patients underwent ultrasonography (7 children did not cooperate and were discarded): 74 females and 55 males with a mean age of 9.52 years. Admission was required in 63 subjects and 66 were sent home after clinical evaluation. Abdominal ultrasonography was performed by the radiologist on duty (occasionally paediatric radiologist). Ultrasound examination, for acute appendicitis, had a sensitivity of 94.8%, specificity of 98.8%, positive predictive value of 97.3% and negative predictive value of 97.8%. Abdominal ultrasonography has showed usefulness for surgical pathology discrimination in acute abdominal pain. When ultrasonography is inconclusive, clinical follow-up and periodical ultrasonography results in a positive change in management and treatment.

A fatal case of congenital disseminated Langerhans cell histiocytosis

The case of a newborn male infant with congenital Langerhans cell histiocytosis (LCH) is presented. At birth, showed cutaneous lesions (papules and vesicles with a haemorrhagic aspect), mucosal and ganglionic involvement. Biopsy of these lesions led to the diagnosis of LCH. At 24 hours of life the patient began with respiratory, hepatic, hematological and renal dysfunction, and died at 72 hours of life, despite corticoid treatment. LHC with vesicles and a rapid and fatal development, has previously only been described in three patients. The differential diagnosis of a disseminated and hemorrhagic vesicular eruption in a newborn infant is extensive and must include LHC.

Wet umbilicus caused by pancreatic heterotopia in urachal remains

Drainage from the umbilicus may be due to the presence of structures derived from the vitelline duct or urachus, granulomas, ectopic tissue, or poor hygienic practice. This paper discusses the case of a 6-month-old infant with a wet umbilicus caused by ectopic pancreatic tissue, in urachal remains. No similar cases have been found in the literature.

[Rupture of a gastrostomy button. Importance of choosing the adequate material]

PEG is a safe, effective and widely used modality for nutritional andpharmacological enteral support in children. Rupture of the gastrostomy button during replacement is a very infrequent complication that may be avoided by choosing the adequate tube.

An experimental model for the prevention of postanastomotic tracheal stenosis

OBJECTIVE

The aim of the current study is to determine the efficiency of an external prosthesis made of expanded polytetrafluoroethylene reinforced with a continuous silicone spiral to prevent postanastomotic stenosis after surgical correction of extensive tracheal defects in rabbits.

METHODS

Forty-five rabbits were used, divided into three groups of 15 animals each. Group A was the control group. Group B animals underwent resection of six-ring segments of the cervical trachea and primary anastomosis. The procedure used in group C was similar to that used in group B, but the tracheal anastomosis was supported by an external expanded polytetrafluoroethylene prosthesis.

RESULTS

Direct anastomosis after resection of six tracheal rings caused anastomotic stenosis in 100% of the animals. We did not observe tracheal stenosis in any rabbit when we applied an expanded polytetrafluoroethylene tube as an external stent for the tracheotracheal suture.

CONCLUSION

We conclude that an external stent can be used to prevent tracheal stenosis resulting from the resection of six cervical tracheal rings in rabbits.

[Cortical fracture of the sternum in a child: an infrequent case]

We report the case of a six-year-old girl who suffer an isolated sternal fracture due to hyperflexion of the thorax (while she was playing on a jumping-bed). On clinical examination, only slight tenderness and pain with compression of sternum was found. Chest X-ray demonstrated a fracture of the body of the sternum without other findings. The patient was admitted, observed during 12 hours with ECG monitoring and discharged because no cardiac or pulmonary pathology appeared. We present this case because fracture of the sternum in a child is rare, especially if road-traffic accident with seat belt injury is not implicated as a cause.

[Propofol in continuous perfusion as anesthetic in experimental surgery in the rabbit]

OBJECTIVES

To study anesthesia with intramuscular ketamine chlorohydrate and continuous intravenous perfusion of propofol (2.6 phenyl diisopropyl) in 30 white New Zealand rabbits undergoing tracheal and vascular surgery and experimental bronchoscopy without mechanical ventilation.

MATERIAL AND METHOD

The animals were monitored by transcutaneous pulse oximetry and were sedated before canalization of the auricular vein. Oxygen was administered under a bell at a rate of 5 l/min. Variables recorded were heart and respiratory rates, oxygen saturation, blink reflex, and movements during surgery. The anesthetic protocol consisted of sedation (intramuscular ketamine chlorohydrate 50 mg/kg), followed by induction (intravenous propofol 3 mg/kg), and maintenance with intravenous infusion of diluted propofol in 2 phases as follows: a loading dose of 1.2 mg/kg/min first, followed by maintenance with 0.9 mg/kg/min propofol in dextrose at 5% concentration (4 mg/ml).

RESULTS

The procedure afforded adequate anesthesia for surgery lasting up to 70 min. Vital signs were stable in all animals. The perfusion rate was modified during surgery in 8 animals, in 5 because of superficial anesthesia and in 3 because of respiratory depression. Respiratory rate was the only parameter that was significantly correlated with depth of anesthesia and propofol dose. Postanesthetic recovery was rapid in all animals. No cases of heart/respiratory failure or death occurred.

CONCLUSIONS

The proposed method is useful for anesthetizing the rabbit, as it renders mechanical ventilation unnecessary. Only simple monitoring of respiratory rate is required.