Effects of different doses of apomorphine on GAD activity in rat substantia nigra

The effects of different doses of the dopamine (DA) receptor agonist apomorphine on the activity of the γ-aminobutyric acid (GABA)-synthesizing enzyme glutamic acid decarboxylase (GAD, EC 4.1.1.15) were investigated in rat substantia nigra in comparison with haloperidol and sulpiride, two DA receptor blocking agents. Results obtained show that low doses (10,35 μg/kg, s.c.) of apomorphine induce a decrease in nigral GAD activity whilst an opposite effect is observed with the highest dose (1000 μg/kg, s.c.). No significant change is observed following injection of the intermediate doses (100 and 500 μg/kg, s.c.). Moreover, sulpiride at the dose used (2 mg/kg, i.p.) induces an increase in GAD activity whilst no effect follows systemic injection of the same dose of haloperidol. The results are discussed in light of recent neurochemical and behavioral data.

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Sommario Sono stati studiati gli effetti comparativi dell' apomorfina, agonista recettoriale dopaminergico, e di due dopamino-bloccanti, l'aloperidolo ed il sulpiride, sull'attività glutamato decarbossilasica nella sostanza nera di ratto. I risultati ottenuti dimostrano che basse dosi (10,35 μg/kg, s.c.) di apomorfina inducono un decremento dell'attività GAD nigrale mentre un effetto opposto è indotto dalla dose più alta (1000 μg/kg, s.c.). Le dosi intermedie (100 e 500 μg/kg, s.c.) non inducono alcuna significativa modificazione. Il sulpiride alla dose usata (2 mg/kg, i.p.) causa un incremento dell'attività GAD mentre nessun effetto si osserva a seguito della somministrazione sistematica di aloperidolo. I risultati sono discussi alla luce di recenti dati neurochimici e comportamentali.

     

Analysis of perpetrator admissions to inflicted traumatic brain injury in children

BACKGROUND: Scientific and courtroom debate exists regarding the timing of onset of symptoms and the mechanism of injury in infants and children with inflicted traumatic brain injury (ITBI). OBJECTIVES: To determine the time interval between ITBI and the onset of symptoms and to explore the mechanism of ITBI. DESIGN, SETTING, AND PATIENTS: Retrospective review of all cases of pediatric ITBI admitted between January 1, 1981, and July 31, 2001, to a large academic medical center and cases admitted to 2 additional academic institutions between January 1, 1996, and August 31, 2000, and January 1, 2001, and July 31, 2001, comparing 81 cases of ITBI in which perpetrators admitted to abuse with 90 cases in which no abuse admission was made. The patients with perpetrator admissions to ITBI consisted of 53 boys (65%) and 28 girls (35%). Their ages ranged from 2 weeks to 52 months. MAIN OUTCOME MEASURES: Characteristics associated with perpetrator admissions to ITBI in children. RESULTS: Shaking was the most common mechanism of injury among all cases with perpetrator admissions: 55 (68%) of the 81 perpetrators admitted to shaking the children. Impact was not described in 44 (54%) of the 81 cases. In cases in which only impact was described, 60% (12/20) of the children showed skull or scalp injury, compared with 12% (4/32) with skull or scalp injury in the shake only group. In 52 (91%) of 57 cases in which the time to the onset of symptoms was described, symptoms appeared immediately after the abuse. In 5 cases (9%), the timing of symptoms was less clear, but they occurred within 24 hours. None of the children were described as behaving normally after the event. CONCLUSIONS: The symptoms of inflicted head injury in children are immediate. Most perpetrators admitted to shaking without impact. These data, combined with the relative lack of skull and scalp injury, suggest that shaking alone can produce the symptoms seen in children with ITBI.     

The therapeutic challenges of dual diagnosis: TBI/SCI

Rehabilitation centres provide therapeutic intervention to both patients with traumatic brain injury (TBI) and spinal cord injury (SCI). Patients with a dual diagnosis of TBI and SCI present a challenge to the rehabilitation professional. Previous studies indicate an incidence of concomitant TBI and SCI to be between 24-59%. Many research articles discuss how a diagnosis of TBI is often missed during the medical examination of a person with a suspected SCI. This article will focus on the implications of dual diagnosis encountered during the rehabilitation process. A case study is used to highlight the challenges presented by the cognitive impairments of a TBI in combination with the motoric deficits of SCI. Management strategies utilised by the rehabilitation team are discussed.     

Experimental posterolateral spinal fusion with porous ceramics and mesenchymal stem cells

Alternatives to autogenous bone graft for spinal fusion have been investigated for many years. It has been shown that osteoconductive materials alone do not give a rate of fusion which is comparable to that of autogenous bone graft. We analysed the effectiveness of porous ceramic loaded with cultured mesenchymal stem cells as a new graft material for spinal fusion in an animal model. Posterolateral fusion was carried out at the L4/L5 level in 40 White New Zealand rabbits using one of the following graft materials: porous ceramic granules plus cultured mesenchymal stem cells (group I); ceramic granules plus fresh autogenous bone marrow (group II); ceramic granules alone (group II); and autogenous bone graft (group IV). The animals were killed eight weeks after surgery and the spines were evaluated radiographically, by a manual palpation test and by histological analysis. The rate of fusion was significantly higher in group I compared with group III and higher, but not significantly, in group I compared with groups II and IV. In group I histological analysis showed newly formed bone in contact with the implanted granules and highly cellular bone marrow between the newly formed trabecular bone. In group II, thin trabeculae of newly formed bone were present in the peripheral portion of the fusion mass. In group III, there was a reduced amount of newly formed bone and abundant fibrous tissue. In group IV, there were thin trabeculae of newly formed bone close to the decorticated transverse processes and dead trabecular bone in the central portion of the fusion mass. In vitro cultured mesenchymal stem cells may be loaded into porous ceramic to make a graft material for spinal fusion which appears to be more effective than porous ceramic alone. Further studies are needed to investigate the medium- to long-term results of this procedure, its feasibility in the clinical setting and the most appropriate carrier for mesenchymal stem cells.