Intracortical circuits, sensorimotor integration and plasticity in human motor cortical projections to muscles of the lower face

Previous studies of the cortical control of human facial muscles documented the distribution of corticobulbar projections and the presence of intracortical inhibitory and facilitatory mechanisms. Yet surprisingly, given the importance and precision in control of facial expression, there have been no studies of the afferent modulation of corticobulbar excitability or of the plasticity of synaptic connections in the facial primary motor cortex (face M1). In 25 healthy volunteers, we used standard single- and paired-pulse transcranial magnetic stimulation (TMS) methods to probe motor-evoked potentials (MEPs), short-intracortical inhibition, intracortical facilitation, short-afferent and long-afferent inhibition and paired associative stimulation in relaxed and active depressor anguli oris muscles. Single-pulse TMS evoked bilateral MEPs at rest and during activity that were larger in contralateral muscles, confirming that corticobulbar projection to lower facial muscles is bilateral and asymmetric, with contralateral predominance. Both short-intracortical inhibition and intracortical facilitation were present bilaterally in resting and active conditions. Electrical stimulation of the facial nerve paired with a TMS pulse 5-200 ms later showed no short-afferent inhibition, but long-afferent inhibition was present. Paired associative stimulation tested with an electrical stimulation-TMS interval of 20 ms significantly facilitated MEPs for up to 30 min. The long-term potentiation, evoked for the first time in face M1, demonstrates that excitability of the facial motor cortex is prone to plastic changes after paired associative stimulation. Evaluation of intracortical circuits in both relaxed and active lower facial muscles as well as of plasticity in the facial motor cortex may provide further physiological insight into pathologies affecting the facial motor system.

Innovative treatment approaches in schizophrenia enhancing neuroplasticity: aerobic exercise, erythropoetin and repetitive transcranial magnetic stimulation

Schizophrenia is a brain disorder associated with subtle, but replicable cerebral volume loss mostly prevalent in frontal and temporal brain regions. Post-mortem studies of the hippocampus point to a reduction of the neuropil constituting mainly of synapses associated with changes of molecules mediating plastic responses of neurons during development and learning. Derived from animal studies interventions to enhance neuroplasticity by inducing adult neurogenesis, synaptogenesis, angiogenesis and long-term potentiation (LTP) were developed and the results translated into clinical studies in schizophrenia. Out of these interventions aerobic exercise has been shown to increase hippocampal volume, elevate N-acetyl-aspartate in the hippocampus as neuronal marker, and improve short-term memory in schizophrenia. The hematopoietic growth factor erythropoetin (EPO) is involved in brain development and associated with the production and differentiation of neuronal precursor cells. A first study demonstrated a positive effect of EPO application on cognition in schizophrenia patients. In randomised controlled studies with small sample size, the efficacy of repetitive transcranial magnetic stimulation (rTMS), a biological intervention focussing on the enhancement of LTP, has been shown for the improvement of positive and negative symptoms in schizophrenia,. The putative underlying neurobiological mechanisms of these interventions including the role of neurotrophic factors are outlined and implications for future research regarding neuroprotection strategies to improve schizophrenia are discussed.

Histopathologic resolution of adult liver transplantation adenovirus hepatitis with cidofovir and intravenous immunoglobulin: a case report

Adenovirus (ADV) infections in adult solid organ transplant recipients, although rare, are associated with high mortality. There are no randomized controlled trials establishing the efficacy of specific treatment modalities. To our knowledge apparent response to treatment with combination therapy with intravenous cidofovir (CDV) and immunoglobulin (IVIG) has only been demonstrated in 2 adult renal transplant recipients in whom ADV was documented in body fluids only. We describe an adult liver transplant recipient diagnosed with ADV hepatitis based on positive immunohistochemical staining of a liver biopsy specimen, positive blood ADV DNA polymerase chain reaction (PCR), and treated with the combination of CDV and IVIG. We demonstrated both clearance of viremia and histopathologic resolution of the hepatitis despite the patient's fatal outcome. To our knowledge this is the only case documenting eradication of tissue-invasive ADV disease in any solid organ transplant recipient using CDV and IVIG. This case provides evidence to support the use of this drug combination, which has many potential toxicities that might discourage its use otherwise.

Aspects of deceased organ donation in paediatrics

Organ transplantation offers children in acute or chronic severe organ failure similar opportunities to adults. However, while the number who might benefit is relatively low, significantly fewer cadaveric donors exist for any given child compared with an adult. Incompatible organ size and relatively low donation rates mean that despite living parental donation and innovations to reduce donated organ size, children die before organs become available. The severity of the UK situation is compounded by restrictions on paediatric living donation, uncertainties over the application of brain death criteria, and ethical concerns about the use of donation after circulatory death. The UK Department of Health's Organ Donation Task Force suggested the means by which the adult donor pool might be increased, recommending that outstanding ethical and legal issues be resolved, but made no specific recommendations about children.

Total antioxidant status and oxidative stress and their relationship to total IgE levels and eosinophil counts in children with allergic rhinitis

BACKGROUND

Oxidative stress may play a role in the pathophysiology of several diseases including allergic rhinitis.

OBJECTIVES

To evaluate whether plasma total oxidant status (TOS) in the form of plasma reactive oxidants differs between children with allergic rhinitis and healthy controls and to investigate associations between plasma antioxidants and other allergic rhinitis-related immunological markers.

MATERIALS AND METHODS

Plasma total antioxidant status (TAS), TOS, total eosinophil count, and total serum immunoglobulin (Ig) E levels were measured in 106 children newly diagnosed with allergic rhinitis and 70 nonallergic children (7-12 years of age). Plasma TAS and TOS were measured using novel automated measurement methods. Blood eosinophils (absolute counts and percentage of total white blood cells) and total IgE were elevated in children with allergic rhinitis after adjusting for age and sex.

RESULTS

TAS and TOS were higher in the patient group than in the control group (P<.001 and P<.002, respectively). The association between plasma TAS and TOS and allergic rhinitis status was similar when eosinophils, total IgE, and allergic sensitization were included as possible confounders in logistic regression models. Multivariate logistic regression identified allergic rhinitis as the only independent factor contributing to TOS.

CONCLUSION

Plasma TAS and TOS levels are elevated in children with allergic rhinitis. Moreover, the high level of TOS indicates that these patients are exposed to severe oxidative stress. This stress factor may have a role in the pathogenesis of allergic rhinitis.

Facial Nerve Monitoring under Neuromuscular Blockade

The characteristics of facial nerve electromyography at various levels of neuromuscular blockade are unclear. Partial blockade is well known to facilitate anesthetic safety and management. However, the use of neuromuscular blockage in many skull base procedures is avoided to allow intraoperative facial nerve monitoring.We studied the influence of various levels of neuromuscular blockade on facial nerve stimulation in the New Zealand white rabbit. The facial nerve was exposed in the middle ear of six rabbits. Using electromyographic-type facial nerve monitor, we recorded the facial electromyography signals in these rabbits at increasing levels of vecuronium-induced neuromuscular blockade. All animals demonstrated reliable facial electromyography response at all levels of partial neuromuscular blockade (P < .02). Five of the six animals could be monitored throughout complete blockade. These results clearly demonstrate that rabbit facial electromyography monitoring is possible under neuromuscular blockade. The effect of neuromuscular blockers on facial electromyography monitoring deserves further study, as partial blockade would greatly facilitate the management of anesthesia in otologic, neurotologic, and skull base surgery.

Manipulating atomic fragmentation processes by controlling the projectile coherence

We have measured the scattering angle dependence of cross sections for ionization in p+H2 collisions for a fixed projectile energy loss. Depending on the projectile coherence, interference due to indistinguishable diffraction of the projectile from the two atomic centers was either present or absent in the data. This shows that, due to the fundamentals of quantum mechanics, the preparation of the beam must be included in theoretical calculations. The results have far-reaching implications on formal atomic scattering theory because this critical aspect has been overlooked for several decades.

Treatment-related morbidity in atypical teratoid/rhabdoid tumor: multifocal necrotizing leukoencephalopathy

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is an aggressive malignant brain tumor that, since it was first identified, has been treated with aggressive treatment regimens, e.g. high-dose chemotherapy with stem cell rescue and early radiotherapy. We reviewed our experience because of concerns with respect to treatment-related toxicity in our patients.

METHODS

Seven patients with a median age at presentation of 18 months were diagnosed with AT/RT between 1996 and 2006. Tumor location was supratentorial in 2 patients, in the posterior fossa in 4 and spinal in 1. Gross total resection was performed in 1 patient, subtotal resection in 5 and biopsy only in 1. Adjuvant treatment consisted of chemotherapy and radiotherapy in 5 patients.

RESULTS

Median progression-free survival was 4 months, and median overall survival was 7 months. Two children are alive at 44 and 102 months. Significant surgical and chemotherapy-related morbidity was seen. Biopsy-proven multifocal necrotizing leukoencephalopathy (MNL) was seen in one patient who is alive 44 months after diagnosis. Another patient who was thought to have recurrent tumor in the brainstem 9 months after diagnosis had imaging findings compatible with MNL.

CONCLUSION

Although improving results are reported for AT/RT using intensive treatment regimens, treatment-related morbidity is considerable in this young patient population.

Outcomes following infant listing for cardiac transplantation: the impact of strategies introduced to counteract limited donor availability

BACKGROUND

Survival following cardiac transplantation in infancy has improved substantially. There is a growing shortage of donors, the impact of which may be offset by increase in ABO-incompatible transplants, size-mismatching and mechanical support. The authors reviewed their results and outcomes following infant listing for cardiac transplantation over 22 years.

METHODS

Children <12 months at time of listing for cardiac transplant in 1987-2008 were identified using the departmental cardiopulmonary transplant database. Details were obtained from databases and hospital medical records and subdivided into two eras, 1987-1997 and 1998-2008.

RESULTS

In 1987-2008, 49 infants were listed, and 28 (57%) underwent cardiac transplantation (12 in 1987-1997 and 16 in 1998-2008). 15 patients (31%) died on the waiting list, 6 patients were delisted (5 of these because of recovery of cardiac function). There was a decrease in suitable donor offers from a mean of 36 per year in 1996-2000 to 11 per year in 2001-2006 (p=0.008). In 1998-2008, nine listed infants were on mechanical support; there were seven ABO-incompatible transplants, and all transplants were size-mismatched with donors on average 2.7 times heavier than recipients. Waiting times decreased from median 83 to 47 days. Six (21%) of the transplanted patients died, the majority in 1987-1997 and perioperatively.

CONCLUSIONS

There has been a fall in suitable donors for infant cardiac transplants over time despite increased demand. However, the introduction of size-mismatching, ABO-incompatible transplants and mechanical support has enabled an increase in the number of transplants to be carried out despite this fall in donor numbers. Outcomes following transplantation have improved over time.

Improvement of steatosis after interferon therapy in HCV genotype 4 is related to weight loss

INTRODUCTION

Hepatic steatosis is common in patients with chronic hepatitis C virus (HCV) infection, and its occurrence may be related to both host and viral factors. Relationship between improvement in steatosis and response to anti-viral treatment remains unclear. This study assessed the factors associated with steatosis in patients infected with genotype 4 HCV, and to correlate degree of changes in steatosis with host factors and response to treatment.

METHODS

Records of 175 patients with chronic genotype 4 HCV infection, who had received interferon and ribavirin combination therapy, were reviewed retrospectively to extract data on body mass index (BMI), presence of diabetes mellitus, and liver histology findings. Paired BMI data and liver biopsies (pre- and 24-weeks post-treatment) were available in 86 patients. Baseline steatosis and its changes (before and after treatment) were the dependent variables in a univariate and multivariate analyses.

RESULTS

Steatosis was found in 88/175 (50.3%) of baseline biopsies. Its presence was related to baseline BMI (r=0.33, P<0.01), but not with viral load, or grade of liver inflammation or fibrosis. On follow up, improvement in steatosis was significantly associated with degree of weight loss but not with response to anti-viral treatment.

CONCLUSION

Steatosis is common in genotype 4 HCV infection, and its presence appears to be related to high BMI, but not to viral load or degree of liver injury.

The use of E-test for the drug susceptibility testing of Mycobacterium tuberculosis - a solution or an illusion?

AIM

To evaluate E-test as a tool for rapid determination of drug susceptibility against the conventional LJ method focusing on reliability, expense, ease of standardization and performance of the technique in low resource settings.

MATERIALS AND METHODS

A total of 74 clinical isolates (2004-2005) of Mycobacterium tuberculosis were tested using E-test for susceptibility to streptomycin (STM), isoniazid (INH), rifampicin (RIF) and ethambutol (EMB) by E-strip and LJ (LJPM) proportion methods.

RESULTS

The LJPM method, the gold standard, detected resistance against STM in 16.2%, INH in 40.5%, RIF in 18.9% and EMB in 27% cases. In comparison, the resistance values showed by E-test was 66.67% for STM, 57.14% for INH 71.43% for RIF and 80% for EMB. The susceptible correlation was 90.32% for STM, 73.91% for INH, 93.33% for RIF and 59.26% for EMB. E-test correctly identified only eight of the 12 (66.6%) MDR isolates and wrongly identified four isolates which were not MDR. The overall agreement between the two methods was only 48.6%. Resistant isolates showed false positive resistance observed while using E-strip towards all the drugs.

CONCLUSION

E-strips are not quite feasible as a replacement for LJ-proportion method on a large scale due to high risk of cross contamination, laboratory infection, expense associated with it and high false positive resistance observed to all first line drugs. However, the good correlation observed for RIF between the two methods indicates that E-test could contribute to the role in rapid screening of MDR TB isolates as rifampicin mutations are invariably observed in MDR TB isolates.

Repetitive transcranial magnetic stimulation for the treatment of negative symptoms in residual schizophrenia: rationale and design of a sham-controlled, randomized multicenter study

Current meta-analysis revealed small, but significant effects of repetitive transcranial magnetic stimulation (rTMS) on negative symptoms in patients with schizophrenia. There is a need for further controlled, multicenter trials to assess the clinical efficacy of rTMS on negative symptoms in schizophrenia in a larger sample of patients. The objective of this multicenter, randomized, sham-controlled, rater- and patient-blind clinical trial is to investigate the efficacy of 3-week 10-Hz high frequency rTMS add on to antipsychotic therapy, 15 sessions per 3 weeks, 1,000 stimuli per session, stimulation intensity 110% of the individual motor threshold) of the left dorsolateral prefrontal cortex for treating negative symptoms in schizophrenia, and to evaluate the effect during a 12 weeks of follow-up. The primary efficacy endpoint is a reduction of negative symptoms as assessed by the negative sum score of the positive and negative symptom score (PANSS). A sample size of 63 in each group will have 80% power to detect an effect size of 0.50. Data analysis will be based on the intention to treat population. The study will be conducted at three university hospitals in Germany. This study will provide information about the efficacy of rTMS in the treatment of negative symptoms. In addition to psychopathology, other outcome measures such as neurocognition, social functioning, quality of life and neurobiological parameters will be assessed to investigate basic mechanisms of rTMS in schizophrenia. Main limitations of the trial are the potential influence of antipsychotic dosage changes and the difficulty to ensure adequate blinding.

Three-body dynamics in single ionization of atomic hydrogen by 75 keV proton impact

Doubly differential cross sections for single ionization of atomic hydrogen by 75 keV proton impact have been measured and calculated as a function of the projectile scattering angle and energy loss. This pure three-body collision system represents a fundamental test case for the study of the reaction dynamics in few-body systems. A comparison between theory and experiment reveals that three-body dynamics is important at all scattering angles and that an accurate description of the role of the projectile-target-nucleus interaction remains a major challenge to theory.

Multicenter experience of ABO-incompatible pediatric cardiac transplantation

Although ABO blood group incompatible cardiac transplantation in neonates and infants reduces waiting list mortality without compromising outcome, the technique has not been adopted by all centers, and to date Toronto remains the only center to have published results from a large case series. We present a review of ABO-incompatible heart transplantation in the United Kingdom (UK) where current recipient selection criteria differ somewhat from those used in the United States (US) and Canada. Between February 2000 and November 2006, 21 ABO-incompatible cardiac transplants were performed in children aged 2-40 months (median 10.0). Immunosuppression followed standard regimens. Pretransplant donor-specific isohemagglutinins of >1:4, (the UNOS cutoff), were present in five patients and reduced by plasma exchange. After transplantation, 19/21 recipients demonstrated persisting deficiency of donor-specific isohemagglutinins. Significant donor-specific isohemagglutinins levels were detected repeatedly in 2/21 recipients who have shown no clinical or biopsy evidence of rejection. All recipients survive without retransplantation and there have been no episodes of humoral rejection. We conclude it is possible for other centers to replicate the excellent results achieved in Toronto and that ABO-incompatible transplantation may be performed successfully in some patients beyond infancy with established isohemagglutinin production providing preoperative antibody removing strategies are used.

Eumycetoma pedis due to Exophiala jeanselmei

A case of eumycetoma of foot in an 8-year old male child was clinically diagnosed as chronic osteomyelitis and was microbiologically confirmed as eumycetoma. The case is being reported for its uncommon clinical presentation and etiological agent, Exophiala jeanselmei. The patient recovered completely after treatment with ketoconazole.

Ageing in Marfan syndrome

AIMS

Marfan syndrome (MFS) is a dominantly inherited connective tissue disorder caused by mutations in the fibrillin-1 gene. Past research has focused on younger patients as lifespan was known to be significantly reduced. This study aims to describe the complications, including those affecting the eyes, heart and musculoskeletal system, faced by older survivors.

METHODS

All 2500 patient records from the National Marfan Syndrome Clinical Database were searched for suitable participants aged 50 or older. One hundred and fifty-six questionnaires were posted to patients with MFS. These patients were sent a detailed questionnaire regarding medical aspects of their disease. Those included in the study were sent questionnaires for spouses and friends (not blood relatives) to complete, to provide control data. Other age- and sex-matched controls were recruited locally.

RESULTS

Sixty questionnaires from patients with MFS (35%) were returned and eligible for inclusion in the study, comprising 28 female patients and 32 male patients with a median age of 57. We recruited 56 eligible controls. Our results revealed that patients over 50 years of age with MFS may be at a higher risk than previously assumed for retinal detachment (reported by 24% of our respondents) and cardiovascular abnormalities (42% have had past aortic surgery; 53% report palpitation). Lesser known complications were also reported, including cataract (reported by 27%).

CONCLUSIONS

Medical practitioners should be aware of the range of complications that can occur in patients with MFS in addition to the normal ageing process. Health problems in MFS patients over 50 may require investigation and specific therapy earlier than in the normal ageing population, because of the degenerative nature of this genetic condition.