Midline thalamic reuniens lesions improve executive behaviors.

The role of the thalamus in complex cognitive behavior is a topic of increasing interest. Here we demonstrate that lesions of the nucleus reuniens (NRe), a midline thalamic nucleus interconnected with both hippocampal and prefrontal circuitry, lead to enhancement of executive behaviors typically associated with the prefrontal cortex. Rats were tested on four behavioral tasks: (1) the combined attention-memory (CAM) task, which simultaneously assessed attention to a visual target and memory for that target over a variable delay; (2) spatial memory using a radial arm maze, (3) discrimination and reversal learning using a touchscreen operant platform, and (4) decision-making with delayed outcomes. Following NRe lesions, the animals became more efficient in their performance, responding with shorter reaction times but also less impulsively than controls. This change, combined with a decrease in perseverative responses, led to focused attention in the CAM task and accelerated learning in the visual discrimination task. There were no observed changes in tasks involving either spatial memory or value-based decision making. These data complement ongoing efforts to understand the role of midline thalamic structures in human cognition, including the development of thalamic stimulation as a therapeutic strategy for acquired cognitive disabilities (Schiff, 2008; Mair et al., 2011), and point to the NRe as a potential target for clinical intervention.

Histology of solid lateral cervical masses biopsied in children.

INTRODUCTION: Solid cervical lateral neck masses in children may require surgical biopsy to confirm appropriate diagnostic and begin a directed therapeutic treatment. We aimed to describe the contribution of pathological results and compare them with the clinical diagnosis and the paraclinical tools. METHODS: A retrospective review of surgical biopsies for solid lateral neck masses in children over a ten year period in a pediatric tertiary center was conducted. Demographic, imaging, laboratory analysis, surgical and pathological data were collected and analyzed using descriptive statistics with SPSS 17.0. RESULTS: 44 biopsies were done between 2002 and 2012. Inflammatory masses were found in 26/44 biopsies with half of them (13/26) being nontuberculous mycobacterial (NTM) lymphadenitis. Non-inflammatory/benign masses represented 9/44 biopsies and 5/44 masses were of malignant etiology. Malignant masses imaging had a sensitivity and specificity of 33% and 75%, respectively, for ultrasound, whereas Neck CT scan had 33% and 77%, respectively. The contribution of pathological results to the clinical management was questionable in 39% (17/44) of biopsies. CONCLUSION: Inflammatory masses with NTM lymphadenitis were the most common diagnosis. Imaging was not helpful in establishing the diagnosis. Heterogeneity in the management of solid lateral neck masses between clinicians was important and indicates the need for guideline approach.

[The end of vertebroplasties]. / El final de las vertebroplastias.

In 2009, two clinical trials that questioned the usefulness of vertebroplasty for the treatment of osteoporotic fractures compared with conservative treatment were reported in the New England Journal of Medicine, leading to wide debate in the literature. In this article, we provide a critical review of the scientific evidence in this field and discuss our own experience with this technique.

Langerhans' cell histiocytosis of the temporal bone in children.

OBJECTIVE: Langerhans' cell histiocytosis (LCH) is a rare pathology that implies an abnormal proliferation of these kinds of cells associated with a granular infiltration that affects different structures of the human body, including the temporal bone. The authors present their series of LCH of the temporal bone in children at the Sainte-Justine university hospital. The twofold objective of this study is to illustrate the clinical presentation, management and prognosis of this disease, and to compare these results with previously reported series. METHODS: A retrospective study was conducted between 1984 and 2007 with patients diagnosed and treated for a LCH of the temporal bone at the Sainte-Justine university hospital, a paediatric tertiary care center. A chart review was performed to obtain demographic, clinical, paraclinical, and therapeutic data. They were analysed and compared to other published series. Through a MEDLINE query, we found that since 1966, 50 articles dealing with a LCH of the temporal bone have been published. RESULTS: Fifty-nine cases of LCH were diagnosed and among them, 10 children had temporal bone involvement. They were four females and six males with a mean age of 3.28 years. The two most frequent clinical manifestations were the presence of a mass in the temporal region (70%) and otitis (60%). Two of our patients had a unifocal lesion of the temporal bone implicated. Eight patients had a multisystem involvement among which, two showed evidence of organ dysfunction. In 80% of cases, the diagnosis was made by immunohistochemical findings of the S-100 protein and/or the CD1 antigen. The common radiological finding on a skull CT scan is a lytic lesion in the temporal bone. Seven patients were treated by chemotherapy, two were treated by radiotherapy as a primary treatment, and one received radiotherapy for a recurrence on the pituitary gland. Finally, one patient was treated with local steroid injections. Two patients had a recurrence. All our patients were in total remission on a mean average of 1.6 years after the diagnosis. Our results concord with other studies in which the prognosis of unifocal bone disease is excellent and children with a multifocal disease have a survival rate of 65-100%. CONCLUSION: LCH is a rare disease. A high-index suspicion should be raised in the context of a temporal mass, chronic otitis, and otorrhea. A biopsy is recommended in the presence of a temporal bone lytic lesion. Chemotherapy is the preferred therapeutic modality.

Nontuberculous mycobacterial adenitis of the head and neck in children: experience from a tertiary care pediatric center.

OBJECTIVE: To describe our experience with the diagnosis, surgical treatment, and outcome of nontuberculous mycobacterial (NTM) adenitis of the head and neck in children, and to present a preliminary report about the use of NTM skin tests in our institution. STUDY DESIGN: Retrospective study. METHODS: The medical records of all children diagnosed with cervicofacial NTM adenitis were retrospectively reviewed for the period from January 1, 1995, through December 31, 2000. We also examined the use of intradermal skin tests for the diagnosis of NTM infection. RESULTS: Fifty patients were diagnosed with NTM cervicofacial adenitis. Pertinent demographic information, clinical presentation, investigation, and type of diagnostic procedures were documented. Surgical procedures, complications, and relapses were also noted. One unusual case of retropharyngeal adenitis is illustrated. All patients were treated with complete excision of their lesion at the first operation. No major complications were noted. Only one patient relapsed and required a second operation. Forty-one children were skin-tested with NTM antigens. Of these, 30 patients were dual-tested with Purified Protein Derivative (PPD) also. No adverse reactions were noted with the use of skin tests. Sensitivity of NTM antigens alone is 87%. Sensitivity of dual testing is 78%. No patient had a PPD-dominant reaction. CONCLUSION: Surgical excision is the treatment of choice of NTM adenitis because of the high cure rate with a single procedure, the excellent cosmetic result, and the low complication rate. NTM skin tests are safe and could be useful in early diagnosis of the infection but further investigation is needed.

Anterior and posterior middle ear congenital cholesteatomas in children.

Congenital cholesteatomas arise from embryonic epithelial cell rests in the middle ear cleft. We report our series of 19 cases observed in 18 children between 1985 and 1990. Clinical data and surgical observations are analyzed. In regard to the location of the lesions, our findings are consistent with most of what has been reported in the literature. Sixty-eight percent of the lesions originated from the anterosuperior part of the mesotympanum. Only 10% were posterosuperiorly located. Pathogenic mechanisms are discussed with respect to the lesion's primary site.

Enzymatic debridement of corneal ulcers with fibrinolysin and desoxyribonuclease

1. Fibrinolysin and DNAase can effectively debride the necrotic tissue in artificially produced rabbit corneal ulcers without injuring the non-necrotic, viable portion of the cornea2. By comparing the treated and untreated bacterial and chemical corneal ulcers in rabbits, there was noted generally less inflammatory reaction and a faster and better healing in those where enzymatic debridement were done3. The basis for the clinical use of enzymatic debridement of corneal ulcers by fibrinolysin and DNAase has been amply demonstrated. (Summary and conclusions)

Lymphangiomas in children: percutaneous sclerotherapy with an alcoholic solution of zein.

PURPOSE: To determine the efficacy of percutaneous sclerotherapy with an alcoholic solution of zein in lymphangiomas in pediatric patients. MATERIALS AND METHODS: Fourteen patients with macrocystic and mixed lymphangiomas were treated with use of Ethibloc as a sclerosing agent. The procedure was performed with ultrasonographic and/or fluoroscopic guidance. Follow-up clinical and sequential computed tomographic examinations were performed to evaluate regression of the lesion. RESULTS: Regression was excellent in nine (64%) of the 14 lesions: Regression was complete in four lymphangiomas and was to less than 5% of the initial volume in five. Satisfactory results were obtained in the remaining five (36%) of 14 lesions. The most frequent complication was leakage of Ethibloc without important sequelae in 10 of the 14 lymphangiomas. CONCLUSION: Percutaneous sclerotherapy with Ethibloc was a safe and effective procedure in the treatment of macrocystic and mixed lymphangiomas.

Endonasal dacryocystocele of the newborn.

The true incidence of endonasal dacryocystocele in the newborn is probably underestimated; the number of cases in the last few years has increased with better imaging techniques and diagnostic tools. Although infrequent, it must be considered in the differential diagnosis of neonatal respiratory distress and nasal obstruction. These children typically present an endonasal mass under the inferior turbinate, most often associated with inner canthal swelling. This series of four patients represents one of the largest to be reported since the first publication on the subject by Goralowna in 1979.

Neural and myogenic effects of cyclooxygenase products on canine bronchial smooth muscle.

In canine bronchi bathed in 10(-6) M indomethacin (IDM), prostaglandin (PG) E2 inhibited electrical field stimulation (EFS)- and acetylcholine (ACh)-mediated contractions and excitatory junction potentials (EJP) in a concentration-dependent manner without altering the resting membrane potential. EFS-induced EJPs were abolished at 10(-7) M PGE2, which shifted responses to ACh 10-fold rightward. Thus PGE2 predominantly inhibited the release of ACh and secondarily decreased smooth muscle response to ACh. U-46619, an analogue of thromboxane A2 (TxA2), initiated tetrodotoxin- and atropine-insensitive contractions in a concentration-dependent manner. U-46619 (10(-9) M) did not alter significantly EFS- or ACh-stimulated contractions and potentiated EFS amplitude of EJPs without depolarizing muscle cells. Either prejunctional activation of ACh release by TxA2 or postjunctional potentiation of the response to ACh can explain these findings. U-46619 (> or = 10(-8) M) depolarized the membrane potential, initiating oscillations accompanied by a large contraction. Addition of 10(-8) M nitrendipine, but not tetraethylammonium (25 mM), blocked the oscillations selectively. Other prostanoids (PGD2, PGI2, and PGF2 alpha) had no significant effects on canine bronchi. In the absence of IDM, PGE2 accumulated, EFS contractions decreased with time, and EJPs disappeared. We conclude that in canine bronchi PGE2 predominantly inhibits ACh release and endogenous PGE2 acts similarly, whereas TxA2 excites, probably at postjunctional sites.

Neural and myogenic effects of leukotrienes C4, D4, and E4 on canine bronchial smooth muscle.

The leukotrienes (LTs), referred to as the slow-reacting substance of anaphylaxis (SRS-A), are reported to have little or no activity in the canine airway. The objective of this study was to determine whether LTC4, LTD4, and LTE4 (10(-10)-10(-7) M) play a role in neuromuscular control of third- to fifth-order canine bronchi. In the presence of 1 microM indomethacin (Indo), canine bronchial smooth muscle contracted and was depolarized in a concentration-dependent manner by LTC4 or LTD4 but not by LTE4. LTC4 and LTD4 concentration-response curves were not significantly affected when conducted in the presence of any of the following: 10(-7) M propranolol (beta-adrenoceptor antagonist), 10(-6) M chlorpheniramine (H1-receptor antagonist), 10(-6) M ketanserin (nonselective 5-hydroxytryptamine receptor antagonist), 10(-7) M atropine (muscarinic receptor antagonist), and 10(-6) M tetrodotoxin (sodium channel blocker). LTC4 and LTD4 also potentiated electrical field-stimulated (EFS) excitatory junction potentials (EJPs), suggesting a possible prejunctional enhancement of acetylcholine release. In the absence of Indo, no postjunctional responses to LTC4 and LTD4 occurred. Endogenous prostaglandin E2 (PGE2) and 6-keto-PGF1 alpha (a stable metabolite of PGI2) levels from canine bronchi were significantly reduced by Indo. In the presence of Indo, addition of > or = 10(-8) M of PGE2 suppressed contractions to LTC4 and LTD4. These data suggest that the decrease in PGE2 and PGI2 production by Indo is sufficient to unmask the excitatory postjunctional actions of LTC4 and LTD4 on bronchial smooth muscle. Serine borate (45 mM; an inhibitor of gamma-glutamyl transpeptidase, which prevents the conversion of LTC4 to LTD4) increased selectively the contractile activity of LTC4. L-Cysteine (3 mM; an inhibitor of an aminopeptidase, which prevents the conversion of LTD4 to LTE4) enhanced the contractile responses to LTD4. Serine borate increased the amplitude and duration of EFS contractions and potentiated the amplitude of EFS EJPs; the last effects were prevented by nordihydroguaiaretic acid. These and other studies suggest that LTs are synthesized by canine bronchi and have receptors on canine bronchial smooth muscle but that contractions to LTC4 and LTD4 in the canine airway are usually not observed because of the presence of inhibitory prostanoids (PGE2 and PGI2). We suggest that decreases in PGE2 and PGI2 in models of airway disease in combination with increases in LTC4, LTD4, and thromboxane A2 may contribute to airway hyperresponsiveness in vitro.

Effects of inflammatory mediators on canine airway neuromuscular function.

Inflammatory mediators can both enhance or inhibit canine airway reactivity. PGE2 and PGI2 in general are inhibitory, interfering with release of acetylcholine and with responses to bronchoconstrictors. These prostaglandins may be more effective against agonists that open voltage-dependent Ca2+ channels to induce Ca2+ influx and contraction compared with those agonists that release internal Ca2+. Other mediators are excitatory: histamine, PGD2, thromboxane A2 (TxA2), and leukotrienes (LT) C4, D4, and E4. In canine airway only histamine and TxA2 have effects in the absence of indomethacin, i.e., in the presence of the large amounts of PGE2 and PGI2 produced in vitro LTs are ineffective. Effects of TxA2 and histamine may be potentiated if the synthesis of these inhibitory PGs is inhibited. Whether histamine or TxA2 normally promote synthesis and release of PGE2 and PGI2 in a kind of homeostasis remains to be explored. It is also unclear whether pre- as well as post-junctional TxA2 receptors exist and have different pharmacological sensitivities to antagonists. LTC4 and LTD4 also constrict canine bronchi but only when PGE2 and PGI2 synthesis is blocked and, again, whether this is a result of LT-induced release of inhibitory mediators is unknown. The concept that airway responsiveness can be caused by turning off PGE2 and PGI2 production and turning on TxA2 or LT production (or unmasking their actions) needs further exploration. Our recent data suggest that such a mechanism may explain ozone-induced responsiveness in dogs.

The internal calcium store in airway muscle: emptying, refilling and chloride. Possible new directions for drug development.

This review examines the ionic mechanisms underlying acetylcholine (Ach) depolarization of airway smooth muscle and suggests that multiple mechanisms are involved. Increased chloride and nonspecific cation conductance, and decreased or rapidly inactivating potassium conductances seem to be involved. Chloride ions also seem to play an important role in determining whether Ca2+ remains inside or is replenished in the sarcoplasmic reticulum (SR). The physiological role of Ach-induced depolarization is analysed and is suggested to be the promotion of the refilling of Ca2+ stores, partly through a direct refilling of SR-Ca2+ stores by way of an L-type Ca2+ channel. This refilling is promoted by Ca2+ channel agonists and is independent of the transmembrane potential. Ca(2+)-release by a variety of agonists leads to depolarization and stable membrane oscillations which depend on the action of the Ca(2+)-store uptake mechanisms in order to function. These oscillations may play a role in prolonged bronchoconstriction. Better knowledge of the control mechanisms of Cai2+ is likely to reveal new targets for the therapy of asthma and provide a better understanding of the function of airway smooth muscle.

Acetylcholine Ca2+ stores refilling directly involves a dihydropyridine-sensitive channel in dog trachea.

Repetitive stimulation of the smooth muscle with acetylcholine (ACh) in the continuous presence of nifedipine resulted in a progressive decrease in the developed tension. This was associated with a decrease in the content of the agonist-sensitive intracellular Ca2+ stores. Agonist-sensitive internal Ca2+ stores appeared to be readily depleted by successive or prolonged agonist stimulation in Ca(2+)-free medium. The refilling of the empty stores when the muscle is at rest required extracellular Ca2+, was decreased by nifedipine, and was increased by BAY K 8644 and by increased external Ca2+ concentration. Refilling of stores during ACh stimulation in Ca(2+)-containing medium was decreased by nifedipine and by cyclopiazonic acid (CPA), an inhibitor of the sarcoplasmic reticulum (SR) Ca2+ pump, and was potentiated by BAY K 8644. BAY K 8644 reversed the inhibitory effect of CPA on stores Ca2+ refilling. Ryanodine in normal Krebs increased muscle resting tension, an effect not observed in Ca(2+)-free medium, blocked by nifedipine and enhanced by BAY K 8644. We propose that the refilling of ACh-sensitive internal Ca2+ stores involves two distinct pathways, one dependent on the uptake of cytosolic Ca2+ via a CPA-sensitive SR Ca(2+)-adenosinetriphosphatase, and the other pathway dependent on extracellular Ca2+ influx via a dihydropyridine-sensitive Ca2+ channel and is CPA insensitive. The refilling pathway between plasmalemma and SR may involve a plasmalemma L-type Ca2+ channel (dihydropyridine sensitive) and the SR Ca2+ release channel (ryanodine sensitive).

The large vestibular aqueduct syndrome and sensorineural hearing loss in the pediatric population.

Sensorineural hearing loss, associated with a dilated vestibular aqueduct, is often described as progressive. Since 1982, computed tomography of the mastoids has become part of the routine investigation of deaf children at Sainte-Justine Hospital. Using clinical, audiometric and radiological material from 130 patients with sensorineural hearing loss, we identified 18 patients with enlarged vestibular aqueducts. The large vestibular aqueduct population was then compared to the normal vestibular aqueduct patients in regard to the degree and evolution of the sensorineural hearing loss. Progression of hearing loss was noted in 46% of patients in the presence of large vestibular aqueducts as compared to 35% in the absence of this anomaly. Normal radiographic findings did not exclude the possibility of further hearing loss.

Myeloperoxidase deficiency with extensive candidal osteomyelitis of the base of the skull.

A 6-year-old girl had a 7-month history of headaches and painful torticollis. A CT scan of the mastoids showed extensive bone destruction of the base of the skull and C-1. Biopsies of the retropharyngeal area and of the anterior aspect of C-1 were performed: histopathologic findings were suggestive of mycotic infection and cultures were positive for Candida albicans. The child was treated successfully with amphotericin B. The immunologic evaluation demonstrated the absence of myeloperoxidase in the neutrophils.

Dermoid cyst of the Eustachian tube.

A case of congenital dermoid cyst of the Eustachian tube is reported. Only seven similar cases have been found in our review of the literature. The embryology and usual mode of presentation of these cysts are discussed. Finally, a new surgical approach using a combined retro-auricular and protympanic route is presented.

Post-myringotomy care: a prospective study.

Children with tympanostomy tubes have always been considered somewhat handicapped in regard to swimming and bathing. Their parents had to maintain constant surveillance to prevent then from getting water in their ears. A prospective study involving more than 1,000 children was conducted between June 1981 and August 1982 on two groups of randomly selected patients to determine the prevalence of suppurative otitis media and its relationship to bathing and swimming. One group had to follow strict rules to prevent water entering the ear (bathing caps, earplugs) whereas the other group was allowed to bathe and swim without any precaution upon the condition of using a polymyxin B/gramicidin ear drop combination at bedtime on the day they swam. The study shows no increase in prevalence of suppurative otitis media in the "open canal" group as compared to the "closed canal" group. Furthermore, the monthly distribution of infections shows a relatively evan distribution throughout the year. This study implies that swimming and bathing are safe for the vast majority of children with tympanostomy tubes and thus simplifies enormously the post-myringotomy care for the child, the parents, and the physician.