Biomedical subjects

K N North

Publications and source records attributed to K N North.

42 records · Page 3Linked to original sources

PubMed1995

Neonatal-onset propionic acidemia: neurologic and developmental profiles, and implications for management.

OBJECTIVES: To document the clinical and neurodevelopmental profiles of a cohort of patients with neonatal-onset propionic acidemia and to determine the efficacy of current therapy with respect to outcome. METHOD: The clinical, neurologic, and developmental status of six patients was prospectively evaluated during a 15-month period. Previous clinical and biochemical data were ascertained from hospital records to determine longitudinal nutritional status, number of episodes of hyperammonemia with ketoacidosis, and developmental performance with respect to age. RESULTS: No deaths resulted from propionic acidemia since the identification of the oldest patient in the series in 1980. Therapeutic intervention (e.g., gastrostomy tube feeding) resulted in improved nutritional status and possibly contributed to improved survival. All children had hypotonia, resulting in a significant effect on motor development; however, focal neurologic deficits and evidence of movement or seizure disorder were absent. Mild cortical atrophy was evident on cranial magnetic resonance imaging in four patients. All children, including two patients with no significant episodes of hyperammonemia and normal growth since the neonatal period, had a mild to moderate degree of intellectual impairment. CONCLUSIONS: The results of our study suggest that current therapy for neonatal-onset propionic acidemia is associated with improved survival and nutritional status, and an absence of focal neurologic deficits. However, hypotonia and cognitive delay were still present, even in children with "optimal" metabolic control. Additional therapeutic advances are required to improve the developmental and cognitive outcome.

Carboxy-Lyases↗

PubMed1995

Attenuated platelet sensitivity to collagen in patients with neurofibromatosis type 1.

Haemostatis has not previously been studied in patients with neurofibromatosis 1 (NF-1), despite case reports of an association with von Willebrand disease and reported excessive bleeding in those undergoing surgery for neurofibromas. Platelets from NF-1 patients (n = 28) were tested for aggregation and ATP release with agonists including ADP, arachidonic acid, thrombin and collagen. Mepacrine staining of platelets and three different assays for von Willebrand factor (VWF) were also performed. In response to collagen as the platelet agonist, tested at both 2 and 1 micrograms/ml, NF-1 patients had an attenuated rate of aggregation (P < 0.007), aggregation lag phase (P < 0.005) and ATP release (P < 0.045), as well as requiring higher collagen concentrations to attain threshold aggregation response (P = 0.041). Normal platelets resuspended in selected NF-1 plasma exhibited significantly reduced platelet aggregation and release compared to controls, which was not corrected by mixing 1:1 with normal plasma. Collagen binding activity was reduced in NF-1 patients compared with controls (127% v 161%, P = 0.05). As a group, patients with NF-1 display defective platelet function characterized by in vitro evidence of impaired responsiveness to collagen. It is suggested that a plasma factor, present in a significant proportion of NF-1 patients, may interfere with the ability of collagen to interact with other proteins such as von Willebrand factor and the platelet collagen receptor.

Adenosine Triphosphate↗

PubMed1994

Idiopathic hypothalamic dysfunction with dilated unresponsive pupils: report of two cases.

Idiopathic hypothalamic dysfunction is a rare but well-defined entity in childhood characterized by adipsia-hypernatremia, obesity, poor thermoregulation, and disturbance of pituitary function. Two cases of idiopathic hypothalamic dysfunction are described. There are 10 previously reported cases in the literature, and the clinical features are compared. The present cases are unique in that the patients also had bilaterally dilated unresponsive pupils. In the first case, there was no demonstrable pathology at autopsy; in the second case, lymphocytic infiltration of the hypothalamus and midbrain associated with neuronal loss was present at autopsy. Possible etiologies are discussed.

Autopsy↗

PubMed1990

Pseudoseizures caused by hyperventilation resembling absence epilepsy.

During the 4-year period, 1982-1986, 18 patients presented to the Children's Hospital, Camperdown, Sydney, with the following features: (1) Recurrent "absences" clinically indistinguishable from childhood absence epilepsy, (2) Normal clinical examination, (3) Electroencephalogram (EEG) demonstrating normal waking background and sleep activity. On hyperventilation, "absences" occurred, characterized on EEG by a marked build-up of paroxysmal slow-wave activity unassociated with evidence of epileptic activity. We designate these attacks "pseudoseizures caused by hyperventilation resembling absence epilepsy." Individual cases demonstrated a variety of other symptoms consistent with the hyperventilation syndrome. There was an identifiable environmental stress in 13 of the 18 cases. Follow-up of 13 patients after a mean period of 20 months revealed that only two children continued to have occasional absences, associated with a clear history of breathing up when upset. Treatment did not influence outcome. On repeat hyperventilation with EEG and respiratory monitoring, five of the 13 had pseudoseizures. There was no indication that susceptibility to these episodes was associated with an abnormal CO2 response. It is postulated that the occurrence of pseudoseizures is related to cerebrovascular immaturity and an excessive vasoconstrictor response to a given level of CO2.

Adolescent↗

PubMed1989

Fifth day fits in the newborn.

During the 1970s, there was an epidemic of neonatal convulsions occurring in apparently normal babies during the fourth and fifth days of life. This syndrome was noted in France as well as in Australia. A study was undertaken to review the King George V Hospital (KGV) experience with these 'fifth day fitters'. All cases of neonatal convulsions at KGV during the years 1972-85 were reviewed. A total of 94 cases of fifth day fits occurred during this period, accounting for 57% of all neonatal convulsions occurring during 1972-79. The fits occurred in healthy term infants after an uncomplicated pregnancy. They appeared on the fourth and fifth days of life. The seizures lasted an average of 24 h, were refractory to drug therapy and, despite extensive investigation, no cause was found. The infants were assessed as normal at the time of discharge from hospital. Follow-up of these infants was incomplete. However, from the data available, it cannot be assumed to be a benign entity. The 'fifth day fit' syndrome reached epidemic proportions at a number of maternity units during the 1970s. At KGV, no case has been observed since 1982.

Cross-Sectional Studies↗

PubMedDate not supplied

Dermoid of cavernous sinus resulting in isolated oculomotor nerve palsy.

Intracranial dermoid cysts and acquired oculomotor nerve palsies are individually rare in childhood. This report describes a 4-year-old boy with acute oculomotor nerve palsy and pupillary sparing secondary to a dermoid within the lateral wall of the cavernous sinus. The clinical signs resolved after complete surgical excision of the tumor with no evidence of recurrence on computed tomography 1 year later. This is the first case report in childhood of a dermoid within the cavernous sinus and of an isolated oculomotor nerve palsy due to a dermoid cyst.

Blepharoptosis↗