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Biomedical subjects

D Keene

Publications and source records attributed to D Keene.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiological survey of central nervous system germ cell tumors in Canadian children.

OBJECTIVES: To determine the incidence and characteristics of pediatric patients with central nervous system (CNS) germ cell tumors (GCT) in Canada. METHOD: A national retrospective review of hospital charts was done on all patients with CNS GCT diagnosed between 1990 and 2004. Patients had to be under age 18 years at the time of diagnosis of a CNS germ cell tumor and be a resident of Canada. Information extracted included age and year of diagnosis, pathological diagnosis, location of tumor, evidence of disseminated disease at time of diagnosis and biological markers. RESULTS: One hundred and twenty-one cases were identified (83 germinoma; 38 non-germinoma germ cell tumor). The mean annual incidence of CNS GCT was 1.06 per million children (0.7 per million for germinoma; 0.3 per million for NGGCT). Though yearly incidences varied, there was no clear trend to increased incidence. Male predominance was noted (2.4:1 for germinoma; 11:1 for NGGCT). The primary locations were the pineal and suprasellar regions. At the time of diagnosis, disseminated disease was not uncommon (22% germinoma; 32% NGGCT). Beta human gonadotrophin was elevated in the serum, cerebrospinal fluid (CSF) or both in 7% of patients with germinoma and 36% of patients with NGGCT. Elevation of alpha-fetoprotein in serum, CSF or both was seen in 34% of patients with NGGCT. CONCLUSION: The incidence of CNS germ cell tumors in Canadian children is similar to that observed in other Western countries.

Adolescent↗
PubMed2005

The use of regional anaesthesia in patients at risk of acute compartment syndrome.

A delay in the diagnosis of an acute compartment syndrome can be devastating to the patient. The increasing use of regional anaesthesia in the management of orthopaedic and trauma patients raises concerns about the potential for delay in the diagnosis of acute compartment syndrome. We undertook a postal survey to assess the usage of regional anaesthesia in patients with lower limb fractures. The study showed that regional anaesthesia is being used in patients at risk of compartment syndrome and without compartment pressure monitoring equipment being available. The anaesthetists questioned had seen cases of acute compartment syndrome being masked by regional anaesthesia. We recommend that there is an urgent need to establish joint guidelines between the orthopaedic and anaesthetic communities on the usage of regional anaesthesia in patients with lower limb fractures to reduce further morbidity from delays in the diagnosis of compartment syndrome.

Anesthesia, Conduction↗
PubMed2003

Sustainable correction of junctional epidermolysis bullosa via transposon-mediated nonviral gene transfer.

Sustainable correction of severe human genetic disorders of self-renewing tissues, such as the blistering skin disease junctional epidermolysis bullosa (JEB), is facilitated by stable genomic integration of therapeutic genes into somatic tissue stem cells. While integrating viral vectors can achieve this, they suffer from logistical and biosafety concerns. To circumvent these limitations, we used the Sleeping Beauty transposable element to integrate the LAMB3 cDNA into genomes of epidermal holoclones from six unrelated JEB patients. These cells regenerate human JEB skin that is normalized at the level of laminin 5 protein expression, hemidesmosome formation and blistering. Transposon-mediated gene delivery therefore affords an opportunity for stable gene delivery in JEB and other human diseases.

Animals↗
PubMed2000

Temporal lobe focal cortical dysplasia: MRI imaging using FLAIR shows lesions consistent with neoplasia.

Focal cortical dysplasia (FCD), a form of neuronal migration disorder, is a malformative lesion of the neocortex that occurs during development of the brain. It can cause partial and generalized epilepsy. Seizures occur at an early age and are often resistant to medication. Surgical resection has been found to be beneficial in these patients. Dual pathology, in the form of mesial temporal sclerosis, has been associated with FCD. At the Children's Hospital of Eastern Ontario, four patients with temporal lobe FCD have recently, been identified. This paper discusses how these children presented and how they were managed, with particular emphasis on their MRI findings and differential diagnoses. In three of the four patients neuroimaging studies showed lesions consistent with a neoplastic process because of the large volume and mass effect. Radiologically, FCD may mimic the MRI appearance of tumors, such as dysembryoplastic neuroepithelial tumors, primitive neuroectodermal tumors, gangliogliomas, oligodendrogliomas, and astrocytomas. These lesions are best visualized on fluid-attenuated inversion recovery (FLAIR) imaging, a technique that has recently become applicable in the clinical setting, as we help demonstrate in this series. With better MRI capability, milder forms of FCD and microdysplasia may be distinguished.

Brain Diseases↗
PubMed1999

Predictors of seizure outcome following cortical resection in pediatric and adolescent patients with medically refractory epilepsy.

Several preoperative clinical variables have been reported to have value as predictors of seizure outcome following the surgical resection of epileptogenic focus in adults who have had medically refractory epilepsy. The present paper reports the results of a retrospective review of the ability of these variables to predict seizure outcome in a group of pediatric patients who had medically refractory epilepsy and underwent surgical resection of an epileptogenic focus at the Children's Hospital of Eastern Ontario. Variables in this review included age at first seizure, age at time of surgery, duration of seizures, seizure type, sex, family history, etiology, level of intelligence, EEG data, results of imaging studies, findings on examination of the central nervous system, and location and site of surgical resection. We found 64 patients who met the entry criteria for this review. Normal intelligence and tumor as etiology were associated with a good postoperative seizure outcome in patients who had a temporal resection; no variables had positive correlation with outcome in the extratemporal group. Caution must be used in the extrapolation of data and inclusion of studies of predictors of seizure outcome for adults to pediatric age groups.

Adolescent↗
PubMed1999

Epilepsy surgery for 5- to 18-year old patients with medically refractory epilepsy--is it cost efficient?

This study was designed to examine the question of whether cortical resection for children and adolescents with medically refractory epilepsy was less costly and more effective than the medical alternative. The study design used a decision analysis model. Data on outcome probabilities were based on literature review and local experience. The time span of the study was 25 years. Though the initial costs for the surgically treated group were significantly greater than those for the medical group, the time-cost lines intersected at 14 years after surgery. Surgery remained cheaper thereafter.

Adolescent↗
PubMed1998

Bone marrow metastasis in astrocytic gliomata.

With the increasing survival time of many pediatric patients with malignancies, unexpected symptoms or signs require diligent search for rare complications or second cancers related to the disease or treatment. We recently encountered a patient with extensive glioblastoma multiforme who developed pancytopenia six months after completion of treatment with craniospinal radiation and chemotherapy with etoposide and cyclophosphamide. Bone marrow aspirate and biopsy confirmed bone marrow metastasis from the brain tumor. He showed good partial remission with chemotherapy with carmustine and cis-platinum as demonstrated by serial bone marrow aspirate for cytology and cytogenetics and enjoyed good quality of life for eight months. 14 other patients with astrocytic glioma, two of whom are children, are reported in the literature to have diffuse bone marrow metastasis. Therefore, in patients with malignant astrocytic tumor, bone marrow metastasis, though not common, should be considered when bone pain or cytopenias occur, especially when prolonged.

Adolescent↗
PubMed1996

Mseleni joint disease--a molecular genetic approach to defining the aetiology.

Mseleni joint disease (MJD) is an unusual form of progressive and widespread degenerative osteoarthropathy that has been identified in several hundred people in the remote Mseleni region of northern Zululand. Affected individuals experience articular discomfort in childhood and may be seriously handicapped as adults, often requiring prosthetic hip joint replacement. Although the condition clusters in families, there is no evidence of Mendelian inheritance and assessment of affected kindreds has not shown any evidence of genomic imprinting. To date our molecular work-up has entailed the study of 47 affected individuals from MJD kindreds to investigate familial predisposition based on the inheritance of a subset of markers and/or genes on the human genome, particularly those associated with the cartilage matrix. In addition, we have collected blood specimens form 111 unaffected but unrelated individuals from the same population group in order to determine whether any relationship exists between genetic components of the human leucocyte antigen (HLA) system and the MJD phenotype. Our investigations show the following: (i) there is no association between MJD and the HLA system which has previously been associated with non-Mendelian genetic conditions; (ii) COL2A1, which has been implicated in some forms of spondylo-epiphyseal dysplasia, may be involved in at least a subset of MJD patients; and (iii) type VI collagen is overabundant in degenerated hip joint cartilage.

Black People↗
PubMed1995

Autosomal dominant nocturnal frontal lobe epilepsy. A distinctive clinical disorder.

The disorder of autosomal dominant nocturnal frontal lobe epilepsy has recently been identified, and is now delineated in detail. A phenotypically homogeneous group of five families from Australia, Britain and Canada, containing 47 affected individuals, was studied. The largest family contained 25 affected individuals spanning six generations. This disorder is characterized by clusters of brief nocturnal motor seizures, with hyperkinetic or tonic manifestations. Subjects often experienced an aura, and remained aware throughout the attacks. Seizures occurred in clusters (mean eight attacks/night) typically as the individual dozed, or shortly before awakening. The epilepsy usually began in childhood, and persisted through adult life, with considerable intra-family variation in severity. Seizures were often misdiagnosed as benign nocturnal parasomnias, psychiatric and medical disorders. Interictal EEG studies were unhelpful. Ictal video-EEG studies showed that the attacks were partial seizures with frontal lobe seizure semiology. Neuro-imaging was normal. Carbamazepine monotherapy was frequently effective. This disorder showed autosomal dominant inheritance. Recognition of this entity is clinically important for diagnosis, appropriate therapy and genetic counselling. Moreover, this disorder now offers an opportunity to identify a gene for partial epilepsy.

Adolescent↗
PubMed1994

Cardiac and central nervous system vasculitis in a child with dermatomyositis.

Cerebral vasculitis and clinically important myocardial inflammation are rare in juvenile dermatomyositis. We report a previously healthy 6-year-old girl with dermatomyositis who died after a fulminating clinical deterioration. Postmortem examination of the heart revealed characteristic endothelial tubuloreticular aggregates and evidence of capillary necrosis and secondary thrombosis, associated with extensive hemorrhagic myocardial necrosis. Endothelial necrosis was also evident in the cerebrocortical capillaries.

Autopsy↗
PubMed1989

Flunarizine as a supplementary medication in refractory childhood epilepsy: a double-blind crossover study.

We report a double blinded cross-over study involving Flunarizine versus placebo in the treatment of refractory childhood epilepsy. The patients studied were between the ages of 2 and 18; and were having more than 4 seizures per month not responsive to regular anticonvulsant medications. Of the 34 patients treated, 8 had a 50% decrease in their seizures during the placebo phase, 5 had a 50% decrease during the Flunarizine phase, and 1 patient had a 50% increase in seizures while taking Flunarizine. The remaining 25 patients showed no change in seizure activity in either phase. Patients having partial seizures with secondary generalization tended to do better on Flunarizine than those with other seizure types. Monitoring serum Flunarizine levels showed no significant difference between patients having improved seizure control and those who were unimproved. No significant side effects were noted with this medication, nor were any significant drug interactions noted.

Adolescent↗
PubMed1988

Relaxation prophylaxis for childhood migraine: a randomized placebo-controlled trial.

A randomized controlled trial was used to evaluate the effectiveness of relaxation training in the treatment of paediatric migraine. Relaxation training was compared with-two control groups (psychological placebo and 'own best efforts') in a total of 99 children and adolescents with frequent migraine. Daily recording of the headaches following treatment, three months after treatment and at the one-year follow-up indicated that all three treatments were equally effective. The importance of the use of adequate control conditions which generate equivalent expectancies in pain treatment research was confirmed.

Adolescent↗
PubMed1987

Evaluation of information-processing speed and neuropsychological functioning in patients with myotonic dystrophy.

Patients with myotonic dystrophy (MD) were compared to a control group, matched to the patients in important demographic variables including IQ, on the Sternberg Memory Scanning procedure, to investigate the hypothesis of a selective change in speed of information processing in MD patients. The neuropsychological functioning of these MD patients was also compared to normative data to provide a descriptive picture of their abilities; these results were correlated to the factors of age of onset and duration of the disease. Finally, the MD patients were also compared to the defined control group on the neuropsychological measures. There was little evidence of selective slowness of information processing or particular deficit independent of overall IQ. Neuropsychologically, the MD patients as a group performed at the low average level. There was, however, a wide range of abilities, suggesting that MD patients are not a unitary group in terms of neuropsychological functioning. Age of onset of the disease was important, at least for certain results. Further research of the neuropsychological functioning of MD patients must account for the wide range of results, with more precise measures of actual onset of the disease and muscular weakness, in a longitudinal evaluation.

Attention↗
PubMed1986

Temporal lobe gangliogliomas in children.

The ganglioglioma, a mixed tumor with neuronal and glial elements, occurs occasionally in children and young adults. Its incidence, clinical presentation, radiological features, and natural history have not been clearly defined. A review of 111 primary brain tumors treated at our institution shows that 9.0% were gangliogliomas. The temporal lobe was the most common site involved. All patients presented with seizures but were neurologically intact. The CT scan showed a partially calcified mass, frequently isodense or nearly so, with minimal enhancement. Complete removal produced dramatic improvement in seizure control. Radiotherapy and/or chemotherapy are reserved for tumors showing malignant changes in the astrocytic component. Patients with chronic epilepsy, or whose seizures escape control despite anticonvulsants, should be examined with this tumor in mind. Following removal of these low-grade temporal lobe tumors, fewer seizures are seen, and the long-term prognosis is very good.

Adolescent↗