Biomedical subjects

Margaret Lee

Publications and source records attributed to Margaret Lee.

4 recordsLinked to original sources

PubMed2002

Cyclooxygenase inhibitor modulation of dopamine-related behaviours.

The sequential action of phospholipase A(2) and cyclooxygenase leads to the production of prostaglandins in the brain, an event hypothesised to cause dopaminergic stimulation. To investigate this further, we examined the effect of the nonselective cyclooxygenase inhibitors indomethacin and piroxicam on several indices of dopaminergic function in adult male rats. Both drugs inhibited catalepsy induced by the dopamine D1-like receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH23390), the dopamine D2-like receptor antagonist raclopride and by haloperidol, findings in agreement with a dopaminergic effect of cyclooxygenase inhibitors. However, neither cyclooxygenase inhibitor had an effect upon disruption of prepulse inhibition of the auditory startle reflex by amphetamine or on the rate of amphetamine self-administration. Both drugs reduced amphetamine-stimulated locomotor activity. Our data indicate that the mechanism by which cyclooxygenase inhibitors alter motor behaviour is unlikely to be due to a simple direct action at the dopaminergic synapse. Their apparent ability to antagonise hypoactivity without generalised dopaminergic stimulation suggests that other, possibly multiple, neurotransmitter systems may be involved.

Amphetamine↗

PubMed2002

Predicting the decrease of conjugated bilirubin with extracorporeal albumin dialysis MARS using the predialysis molar ratio of conjugated bilirubin to albumin.

Extracorporeal albumin dialysis with the molecular adsorbent recirculating system (MARS) machine is a new supportive intervention for patients with liver failure. It removes bilirubin and other albumin-bound toxins from the patient and has been shown by preliminary studies of liver failure patients to be beneficial. Our study examines the ability of predialysis molar ratio of bilirubin to albumin to predict the decrease of bilirubin by MARS. We had 5 patients and results from 29 treatments. The results showed a significant correlation between the predialysis molar ratio of bilirubin (total and conjugated) to albumin to the reduction in bilirubin (total and conjugated): R(2) = 0.27 and 0.62 respectively, P <.005 for both. There was no significant correlation with the predialysis molar ratio of unconjugated bilirubin to albumin to the reduction in unconjugated bilirubin. The ratio of change in total bilirubin (micromol/L) to the predialysis molar ratio of total bilirubin to albumin and the ratio of change in conjugated bilirubin (micromol/L) to the predialysis molar ratio of conjugated bilirubin to albumin were 6.2 (+/- 4.2) and 10.8 (+/- 4.3), respectively (mean (+/- SD)). The results enable us to predict the likely reduction in bilirubin (especially conjugated) after each MARS treatment and also suggest to us that albumin infusion before MARS treatment may reduce the efficacy of bilirubin removal. Whether this ratio applies to other albumin-bound toxins remains open for investigation.

Bilirubin↗

PubMed2002

Cobalamin C disease presenting as hemolytic-uremic syndrome in the neonatal period.

Anew case of cobalamin C disease associated with hemolytic-uremic syndrome (HUS) in the neonatal period is described. A 28-day-old boy presented with failure to thrive, hypotonia, pancytopenia, and features of HUS (microangiopathic hemolytic anemia, thrombocytopenia, and renal failure). The possibility of the diagnosis of an underlying vitamin B12 disorder was prompted by evidence of megaloblastic changes on the peripheral smear and by finding in the literature a suggested association of neonatal HUS with this cobalamin-related metabolic disorder. Amino acid analysis showed elevated homocysteine levels in the plasma and increased levels of both homocysteine and methyl malonic acid in the urine. Diagnosis of cobalamin C disease was confirmed by complementation studies using skin fibroblasts. Therapy included parenteral hydroxocobalamin, carnitine, and leucovorin calcium (folinic acid). Cobalamin C disease should be considered in the diagnosis of patients presenting with HUS in infancy who have unexplained megaloblastosis, pancytopenia, neurologic impairment, and failure to thrive. Early diagnosis and institution of therapy may be effective in improving survival and quality of life.

Diagnosis, Differential↗

PubMedDate not supplied

Kasabach-merritt phenomenon: a retrospective study of treatment with vincristine.

PURPOSE: Kasabach-Merritt phenomenon (KMP) is characterized by profound thrombocytopenia, microangiopathic hemolytic anemia, a consumptive coagulopathy, and an enlarging vascular lesion. The syndrome develops in infancy and is associated with a high morbidity and mortality rate. The purpose of this study was to assess the effectiveness of vincristine in the treatment of KMP. METHODS: We retrospectively reviewed the clinical and laboratory data of 15 patients with KMP treated with vincristine at 9 institutions across the United States, South America, and Europe. RESULTS: All 15 patients had profound thrombocytopenia and consumption of fibrinogen at presentation. Ten patients had biopsies of their lesions, and results included five (33.3%) kaposiform hemangioendotheliomas, three (20%) tufted angiomas, one lesion (6.7%) with features of both kaposiform hemangioendothelioma and tufted angioma, and one (6.7%) unclassified vascular tumor. All 15 patients had an increase in platelet count of at least 20,000 with an average response time of 4.0 weeks after initiation of vincristine therapy. Thirteen patients had an increase in fibrinogen level of 50 mg/dL with an average response time of 3.4 weeks. In 13 patients there was a significant decrease in the size of the vascular lesion. The average duration of treatment was 21.5 (+/-12.6) weeks. Four patients (26%) relapsed. All four were successfully treated with a second course of vincristine. Complications included one patient with abdominal pain, one patient with transient loss of deep tendon reflexes, and one patient with irritability. CONCLUSION: Vincristine presents a safe and sometimes effective treatment option in the management of KMP.

Antineoplastic Agents, Phytogenic↗