Lack of effect of aspartame or of L-phenylalanine on photically induced myoclonus in the baboon, Papio papio

The effects of large doses of L-phenylalanine and of aspartame on seizure susceptibility and severity have been assessed in baboons Papio papio from Senegal which show photosensitive epileptic responses similar to primary generalised epilepsy in man. L-Phenylalanine, 50, 150 or 450 mg/kg, or aspartame, 300 or 1000 mg/kg, were administered orally. Peak plasma L-phenylalanine concentrations of approximately 2000 mumoles/l occurred 1-4 h after the highest dose of L-phenylalanine or aspartame. The plasma L-phenylalanine to large neutral amino acid ratio increased approximately 30-fold at this time. Compared with water administration there were no changes in epileptic responses 1-5 h after either treatment. In this primate model of epilepsy acute increases in plasma phenylalanine concentration are neither pro- nor anticonvulsant.     

Congenital cardiac malformations in Adams-Oliver syndrome

Whole genomic hprt clones were used in Southern analysis to screen the integrity of the hprt gene in a family that includes a patient with HPRT enzyme deficiency causal to Lesch-Nyhan syndrome. A 5 kb DNA sequence deletion was found to have its endpoints in the first and third introns. The probes identified the carrier status of female family members, aided by an RFLP carried by the mother's normal X-chromosome.     

Immunization-induced inflammatory infiltration of the central nervous system in transgenic mice expressing a microbial antigen in astrocytes

Transgenic mice expressing a defined microbial antigen from central nervous system (CNS) cell type-specific promoters can be utilized to investigate the consequences of induction of peripheral immune responses to foreign antigens produced by different CNS cell types. Immunization of mice expressing β-galactosidase (β-gal) in astrocytes with this protein resulted in antigen-dependent infiltration of the CNS by mononuclear cells, principally CD4⁺ T lymphocytes and monocyte/macrophages. The perivascular and intraparenchymal infiltrates, which were located predominantly in the hippocampal formation and cerebellum, the areas of highest β-gal expression, were associated with astrocytosis, microgliosis, and a generalized increase in blood-brain barrier permeability. The resemblance of these pathological changes to aspects of human immune inflammatory CNS disorders e.g. multiple sclerosis, suggests that an initiating step in the process by which such complex diseases are produced could be the induction of peripheral immune responses to antigens expressed in astrocytes.     

Management of fractures in patients with osteoporosis

The treatment of the most common osteoporotic fractures has been reviewed. In general, early functional treatment is used to allow early restoration of function and weight bearing. Fracture treatment should always be accompanied by an investigation of the bone mass in these patients. Nutritional support and calcium and vitamin supplementation should be provided during the healing phase.     

Magnetic resonance imaging in young adults with cerebral infarction due to moyamoya

The number, size, and location of cerebral infarctions, and blood flow in the middle cerebral artery as seen on proton magnetic resonance imaging were assessed in six white adults with angiographically documented moyamoya. Findings were correlated with clinical presentation, computed tomography, and angiography. Large hemispheric infarctions were found in five hemispheres, predominantly in watershed regions. Subcortical infarctions (n = 56) were found in all hemispheres. They were predominantly located in the centrum semiovale, in the distal beds of supply of the penetrating branches of the anterior and middle cerebral arteries. Infarction of the putamen was found in three hemispheres, caudate nucleus in four, globus pallidus in two, and anterior limb of the internal capsule in two. There were none in the posterior limb of the internal capsule, thalamus, brain stem, or cerebellum. Middle cerebral artery flow was visualized as a signal-void flow sign in only three hemispheres. Cerebral infarctions due to moyamoya are bilateral, multiple, often small, and asymptomatic, affecting predominantly the carotid circulation in watershed regions. Subcortical infarctions in the centrum semiovale and large hemispheric infarctions in hemodynamically compromised areas are the predominant findings.     

The minimum concentration of fibrinogen needed for platelet aggregation using ADP.

OBJECTIVE: Determine the minimum concentration of plasma fibrinogen needed to stimulate the aggregation of platelets, collected from normal subjects, using ADP. DESIGN: Platelet rich plasmas (300 x 10(9) platelets/L) were made and adjusted to final fibrinogen concentrations of 75, 19, 5, and 0 mg/dL using fibrinogen free serum. Each fibrinogen concentration in all twelve subjects was aggregated with ADP SETTING: Research laboratory in the Department of Clinical Laboratory Science at Saint Louis University. PARTICIPANTS: Twelve healthy volunteers of both genders, between the ages of 18 and 60 years who were not pregnant and weighed at least 110 pounds were included in the study. Subjects were excluded from the study if they had ingested aspirin within one week prior to blood collection. In addition, subjects with a history of bleeding disorders such as afibrinogenemia, hypofibrinogenemia, von Willebrand disease, and Bernand-Soulier disease were rejected from the study. MAIN OUTCOME MEASURES: Platelet aggregation tracings were analyzed for amplitude and compared across plasma fibrinogen concentrations. In addition, the type of curve (monophasic vs. biphasic), smoothness and aggregation stability were also noted. RESULTS: The results show that aggregation occurred with every dilution of fibrinogen tested and that the amplitude of the aggregation curves appears not to be dependent on plasma fibrinogen. CONCLUSIONS: The results indicate that platelets from healthy individuals previously exposed to normal fibrinogen levels will aggregate equally well in decreasing plasma fibrinogen concentrations and even in the absence of plasma fibrinogen using ADP as the aggregator.