Approach to seizures in the neonatal period: a European perspective

In the neonatal period, seizures rank among the most common neurological symptoms, often indicating an underlying serious neurological condition. It is remarkable that although new tools have been incorporated into the diagnosis of neonatal seizures, there is no consensus about the therapeutic approach among different doctors and institutions. Hence, although phenobarbital is still considered the initial drug of choice, the protocols reported in the literature show a great variability in the approach to treatment of refractory seizures. We used a questionnaire to gain information regarding the treatment of seizures in the neonatal period in different European institutions. Conclusion: We conclude that phenobarbital is still the initial drug of choice followed by benzodiazepines, except in preterm infants with a birth weight below 1800 g. In refractory seizures, the use of continuous lidocaine infusion is most common. Of note, clinical studies with newer drugs have been mostly performed in the United States but not in Europe.     

Erythropoietin structure-function relationships: high degree of sequence homology among mammals

To investigate structure-function relationships of erythropoietin (Epo), we have obtained cDNA sequences that encode the mature Epo protein of a variety of mammals. A first set of primers, corresponding to conserved nucleotide sequences between mouse and human DNAs, allowed us to amplify by polymerase chain reaction (PCR) intron 1/exon 2 fragments from genomic DNA of the hamster, cat, lion, dog, horse, sheep, dolphin, and pig. Sequencing of these fragments permitted the design of a second generation of species-specific primers. RNA was prepared from anemic kidneys and reverse-transcribed. Using our battery of species-specific 5' primers, we were able to successfully PCR- amplify Epo cDNA from Rhesus monkey, rat, sheep, dog, cat, and pig. Deduced amino acid sequences of mature Epo proteins from these animals, in combination with known sequences for human, Cynomolgus monkey, and mouse, showed a high degree of homology, which explains the biologic and immunological cross-reactivity that has been observed in a number of species. Human Epo is 91% identical to monkey Epo, 85% to cat and dog Epo, and 80% to 82% to pig, sheep, mouse, and rat Epos. There was full conservation of (1) the disulfide bridge linking the NH2 and COOH termini; (2) N-glycosylation sites; and (3) predicted amphipathic alpha- helices. In contrast, the short disulfide bridge (C29/C33 in humans) is not invariant. Cys33 was replaced by a Pro in rodents. Most of the amino acid replacements were conservative. The C-terminal part of the loop between the C and D helices showed the most variation, with several amino acid substitutions, deletions, and/or insertions. Calculations of maximum parsimony for intron 1/exon 2 sequences as well as coding sequences enabled the construction of cladograms that are in good agreement with known phylogenetic relationships.     

Altered Expression of Microtubule-Associated Proteins in Cat Trochlear Motoneurons after Peripheral and Central Lesions of the Trochlear Nerve

Neurons lesioned in the peripheral nervous system (PNS) generally regenerate and survive, while neurons lesioned in the central nervous system (CNS) do not regenerate and often die. Investigators have traditionally compared the neuronal responses to PNS and CNS lesions in two separate populations of neurons. In this study, we compared the effects of PNS and CNS lesions on the expression of cytoskeletal proteins in a single neuronal population, the trochlear motoneurons of the cat. The trochlear nerve was lesioned either unilaterally in the PNS or bilaterally in the CNS (within the anterior medullary velum), and animals were allowed to survive 1, 2, or 4 weeks. Brain sections were reacted immunocytochemically using antibodies against microtubule-associated protein-2 (MAP-2) and a phosphorylated isoform of MAP1B, termed MAP1B-P. MAP-2 immunoreactivity (IR) was significantly decreased in the CNS-lesioned trochlear nucleus, compared to the lesioned and the unlesioned trochlear nucleus of PNS-lesioned animals. MAP1B-P IR was significantly increased in PNS- and CNS-lesioned trochlear axons, compared to axons in the unlesioned trochlear nerve of PNS-lesioned animals, and appeared in a small percentage of PNS- and CNS-lesioned cell bodies. These results support the growing body of evidence that MAP-2 can serve as a marker for cells that will eventually die following neuronal insult. The increased immunostaining of MAP1B-P in lesioned axons and its appearance in lesioned cell bodies are characteristic of the immature CNS and may reflect an initial recapitulation of early development, when the levels of this protein are high.     

False-positive Histoplasma antigenemia caused by antithymocyte globulin antibodies

False-positive Histoplasma antigen results were identified in two patients who received rabbit antithymocyte globulin (ATG, Thymoglobulin(R)) to prevent allograft rejection. To determine the prevalence of false-positive results following the administration of Thymoglobulin, sequential specimens were tested from a cohort of transplant recipients. Of 107 such patients, 17 (15.9%) demonstrated false-positive tests for Histoplasma antigenemia. False antigenemia peaked at 2-4 weeks after ATG administration and cleared over the next few months. Physicians should be aware of the potential for false-positive results in specimens from patients who have received ATG.     

鼓槌石斛中一新的联苄类化合物——鼓槌石斛素

从兰科鼓槌石斛(Dendrobium chrysotoxum)中分得一新的联苄类化合物,经光谱分析(UV,IR,MS,¹HNMR,¹³CNMR和DIFNOE),其结构确定为4-羟基-3,5,3',4'-四甲氧基联苄,命名为鼓槌石斛素。关键词鼓槌石斛;鼓槌石斛素;联苄类化合物。