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Biomedical subjects

M A Matzinger

Publications and source records attributed to M A Matzinger.

At least 19 recordsLinked to original sources
PubMed2005

Radioisotope shuntograms at the Children's Hospital of Eastern Ontario.

INTRODUCTION: Nuclear medicine shuntograms using the radiotracer technetium-99m diethylenetriaminepentaacetic acid have been used for many years as an additional method to assess shunt patency and performance. METHODS: The medical records of all children who had shuntograms performed at the Children's Hospital of Eastern Ontario between January 13, 2000, and January 10, 2003, were retrospectively reviewed. There was a total of 68 procedures in 56 patients with an average age of 9 years 3 months. During the same period there were 123 shunt revisions. RESULTS: Forty-two shuntograms were reported as normal. Of these, ten were identified to be false negative. Two children with fractured shunts had shuntograms performed in order to assess for cerebrospinal fluid flow patency; the shuntograms were identified to be normal, confirming shunt dependence, and the shunt replaced. Twenty-six shuntograms were reported as abnormal in 24 patients; 17 went on to have surgery and the shunt malfunction was confirmed. Seven patients did not require surgery: five were declared shunt independent, two patients clinically improved after severe constipation was treated. CONCLUSIONS: Approximately one fourth of all shuntograms reported as normal are not (false-negative rate=25%). Review of five other major studies between 1980 and 2003 have reported false-negative rates between 2 and 36%, which may be explained by variations in shuntogram protocols. A standardized method is proposed.

Adolescent↗
PubMed2004

Resolution of severe, adolescent-onset hypophosphatemic rickets following resection of an FGF-23-producing tumour of the distal ulna.

Oncogenic hypophosphatemic osteomalacia (OHO) is an uncommon hypophosphatemic syndrome characterized by bone pain, proximal muscle weakness and rickets. It has been postulated that OHO results from overproduction of a humoral phosphaturic factor by an occult tumour. Recently, some OHO tumours have been shown to elaborate fibroblast growth factor-23 (FGF-23), which causes renal phosphate wasting when administered to mice. The purpose of this study was to undertake detailed investigations to confirm the diagnosis of OHO in a pediatric patient and to document the biochemical, radiographic and bone histological phenotype before and after tumour removal. We describe an 11-year-old, previously healthy girl with significant pain and functional disability associated with hypophosphatemic rickets. Circulating 1,25-(OH)(2) vitamin D was very low (14 pM; N: 40-140) while the FGF-23 serum level was markedly elevated [359.5 reference units (RU)/ml, N: 33-105]. An iliac bone biopsy revealed severe osteomalacia, but periosteocytic lesions, as are typical for X-linked hypophosphatemic rickets, were not seen. Sequence analyses of the PHEX and FGF23 genes were normal. A radiographic skeletal survey revealed a small exostosis of the left, distal ulnar metaphysis. A tumour was subsequently removed from this site and the pathology was consistent with benign, fibro-osseous tissue. Serum FGF-23 was normal when measured at 7 h post-operatively, while serum phosphate reached the low-normal range at 16 days following surgery. An iliac bone biopsy taken 5 months after the operation showed improvement, but not yet resolution, of the osteomalacia. Biochemical parameters of bone and mineral metabolism suggested that complete resolution of the osteomalacia was not achieved until 12 months following surgery. One year after tumour removal, the patient was pain-free and had resumed a normal level of activity. The rapid normalization of FGF-23 levels following removal of a benign tumour and the subsequent improvement in the biochemical and histological parameters of bone and mineral metabolism suggest that FGF-23 played a key role in this girl's disease.

Base Sequence↗
PubMed2001

Cerebral vascular events associated with ulcerative colitis in children.

Although peripheral vascular thrombic events are recognized as a serious extra-intestinal complication of inflammatory bowel disease, the occurrence of cerebral vascular events in association with acute exacerbations of this group of diseases is rare. In this article, relevant literature is reviewed and three children, 5, 12, and 13 years of age, who presented with clinical and magnetic resonance imaging evidence of an acute cerebrovascular event in association with an acute exacerbation of their inflammatory bowel disease are described. Except for the presence of anemia, hematologic and coagulation studies were unremarkable, and a search for evidence of a systemic vasculitis proved negative.

Adolescent↗
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↗
PubMed2000

Primary ciliary dyskinesia associated with a novel microtubule defect in a child with Down's syndrome.

We present a child with Down's syndrome, bilateral lower lobe bronchiectasis, sinusitis, and severe ear disease who was found to have a novel ciliary defect, with a frequent, partial absence of the walls of the A subunits of some peripheral doublets. The defect caused the A subunits to be "U-shaped" rather than "O-shaped." A nuclear nasal mucociliary transport study confirmed that this defect was associated with abnormal mucociliary transport. The ciliary defect was not observed in a biopsy performed in a second patient who had Down's syndrome.

Biopsy↗
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↗
PubMed1993

Prevalence of hypertension in children with primary vesicoureteral reflux.

This study was undertaken to determine the prevalence of hypertension in children with primary, uncomplicated vesicoureteral reflux (VUR) and to evaluate the relationship between blood pressure (BP), grade and duration of reflux, and renal scarring. Subjects were identified retrospectively during a 17-year period; of 146 subjects who agreed to participate, 129 (88.4%) were female. Mean age at diagnosis was 5.0 years (range, 1 month to 16 years), and at follow-up was 14.4 years (range, 5 months to 21 years). Mean duration of follow-up was 9.6 years. Renal scarring was detected in 34.3% of patients by intravenous pyelogram, ultrasonography, or both. The BP at diagnosis was linearly related to the grade of reflux, but values were not higher than expected norms for age. At follow-up, mean systolic and diastolic BP were at the 41.6 percentile and the 18.7 percentile, respectively. No patient's BP was above the 55th percentile. After a mean follow-up period of 10 years, we conclude that primary, uncomplicated VUR, regardless of the number of documented urinary tract infections, duration and severity of reflux, modality of therapy, presence of renal scarring, and duration of follow-up, is not associated with the development of hypertension. Hypertension does not appear to be a complication of VUR and urinary tract infection unless there is preexisting dysplasia.

Adolescent↗
PubMed1992

Plain film and CT observations in prostaglandin-induced bone changes.

Prostaglandin E1 intravenous infusion is used in infants with ductal-dependent congenital heart disease to maintain ductal patency and prolong life until palliative or corrective surgery is feasible. Complications of prostaglandin administration include fever, diarrhoea, hypotension, apnoea, bradycardia, pseudowidening of the cranial sutures, underossification of the calvarial bones, periostitis, and skin edema [1-3]. This paper presents dramatic plain radiographic features of prostaglandin-induced bone disease, including periosteal proliferation and the unusual bone-within-bone appearance, and provides the previously unpublished CT correlation.

Alprostadil↗
PubMed1992

Evaluation of renal scars by technetium-labeled dimercaptosuccinic acid scan, intravenous urography, and ultrasonography: a comparative study.

The objective of our prospective study was to compare the sensitivity and specificity of ultrasonography, intravenous pyelography, and dimercaptosuccinic acid scan in detecting scarred kidneys. Twenty-seven consecutive subjects with recurrent urinary tract infections, vesicoureteral reflux, scarred kidneys, or a combination of these problems had all three imaging procedures performed. With the total number of scars serving as the gold standard, the sensitivity (94%) and specificity (100%) in identifying renal scars in children were highest for the DMSA scan. Intraobserver (95%) and interobserver (90%) reliability were also high for the DMSA scan. However, the clinical interpretation of the increased sensitivity of the DMSA scan is unknown. Changes on the scan not identified by intravenous urography may not represent true scars. Research into the long-term significance of these scars is indicated.

Adolescent↗
PubMed1992

Antenatal and postnatal findings in intra-abdominal pulmonary sequestration.

A hyperechoic mass in the right upper quadrant of the abdomen was demonstrated in a fetus by antenatal ultrasonography (US) at 20 and 33 weeks' gestation. Postnatal US, myelography and computed tomography were performed preoperatively; the findings were judged consistent with neuroblastoma. Surgical excision and pathological examination revealed bronchopulmonary sequestration.

Abdominal Neoplasms↗