Biomedical subjects
Daniel Martinez
Publications and source records attributed to Daniel Martinez.
DJ-1 colocalizes with tau inclusions: a link between parkinsonism and dementia.
Two novel mutations recently have been identified in the DJ-1 gene that cause a new form of autosomal recessive, early-onset parkinsonism. Because the pathological role of this protein is unknown, we examined the issue here and report the colocalization of DJ-1 protein within a subset of pathological tau inclusions in a diverse group of neurodegenerative disorders known as tauopathies. Our study extends the view that different neurodegenerative diseases may have similar pathological mechanisms, and that these processes likely include DJ-1.
Impact of right ventricle to pulmonary artery conduit on outcome of the modified Norwood procedure.
BACKGROUND: To determine and compare outcome of the modified Norwood procedure using either a systemic to pulmonary artery (SPA) shunt or right ventricle to pulmonary artery (RV-PA) conduit in a consecutive series of neonates at a single institution. METHODS: The medical records were retrospectively examined for preoperative demographic and echocardiographic data, operative variables, and postoperative clinical and hemodynamic data. From November 2001 to March 2003, 21 neonates had a modified Norwood procedure (SPA shunt, n = 8; RV-PA conduit, n = 13) at a median age of 5 days (range 1 to 18 days) and a median weight of 2.9 kg (range 1.7 to 4.1 kg). Of the 21 infants, 12 were considered high risk due to presence of low birth weight (n = 4), extracardiac or genetic anomalies (n = 5) or obstruction to pulmonary venous return (n = 5). Nine "high risk" infants were in the RV-PA conduit group. RESULTS: Overall Norwood operation survival was 90% (19/21) and did not differ between groups. There were 2/19 interstage deaths and Kaplan-Meier survival at 1 year is 79%. Neonates in the RV-PA conduit group had significantly higher diastolic blood pressures at 1, 6, and 24 hours postoperatively (p < 0.05). Neonates in the SPA shunt group had significantly higher heart rates at 1 hour postoperatively (p < 0.05) than those in the RV-PA group. There was a trend to higher number of ventilatory interventions to balance Qp:Qs in the SPA shunt group (p = 0.06). CONCLUSIONS: In a relatively high-risk group, neonates having an RV-PA conduit as part of the Norwood procedure have favorable postoperative hemodynamics and a good likelihood of stage I survival.
Case report: Survival after deliberate strychnine self-poisoning, with toxicokinetic data.
INTRODUCTION: Strychnine poisoning is uncommon, and in most severe cases, the patient dies before reaching hospital. The management of strychnine poisoning is well documented, although there are few data on the kinetics of elimination of strychnine after overdose. CASE REPORT: A 42-year-old man presented shortly after ingestion of an unknown quantity of strychnine powder. After a respiratory arrest, with intensive supportive management requiring admission to an intensive care unit, he survived. Eight serum samples were taken over the first 5 days and analysed subsequently for strychnine concentrations. RESULTS: The initial concentration at 1.5 hours after ingestion was 4.73 mg/l, falling to 0.38 mg/l at 74 hours postingestion. Serum concentrations followed a monoexponential elimination curve with a calculated elimination half-life of 12 hours. DISCUSSION AND CONCLUSION: Strychnine poisoning presents with classical features, and with early diagnosis and supportive management, the patient can survive. The initial serum concentration of 4.73 mg/l is the highest reported concentration in a patient who has survived. Previous reports of the elimination half-life have suggested it is between 10 and 16 hours, which conforms to the elimination data in our case.
Repetitive mild brain trauma accelerates Abeta deposition, lipid peroxidation, and cognitive impairment in a transgenic mouse model of Alzheimer amyloidosis.
Traumatic brain injury (TBI) increases susceptibility to Alzheimer's disease (AD), but it is not known how TBI contributes to the onset or progression of this common late life dementia. To address this question, we studied neuropathological and behavioral consequences of single versus repetitive mild TBI (mTBI) in transgenic (Tg) mice (Tg2576) that express mutant human Abeta precursor protein, and we demonstrate elevated brain Abeta levels and increased Abeta deposition. Nine-month-old Tg2576 and wild-type mice were subjected to single (n = 15) or repetitive (n = 39) mTBI or sham treatment (n = 37). At 2 d and 9 and 16 weeks after treatment, we assessed brain Abeta deposits and levels in addition to brain and urine isoprostanes generated by lipid peroxidation in these mice. A subset of mice also was studied behaviorally at 16 weeks after injury. Repetitive but not single mTBI increased Abeta deposition as well as levels of Abeta and isoprostanes only in Tg mice, and repetitive mTBI alone induced cognitive impairments but no motor deficits in these mice. This is the first experimental evidence linking TBI to mechanisms of AD by showing that repetitive TBI accelerates brain Abeta accumulation and oxidative stress, which we suggest could work synergistically to promote the onset or drive the progression of AD. Additional insights into the role of TBI in mechanisms of AD pathobiology could lead to strategies for reducing the risk of AD associated with previous episodes of brain trauma and for preventing progressive brain amyloidosis in AD patients.