Spatial and temporal gene expression profiling of the contused rat spinal cord

Microarray technology was used to examine gene expression changes following contusive injury of the adult rat spinal cord. To obtain a global understanding of the changes triggered by the injury, differential gene expression was examined spatially, using tissue samples from the epicenter of injury as well as 1 cm rostral and 1 cm caudal to the epicenter, and temporally, at 3 h, 24 h, 7 days, and 35 days post-injury. To filter out gene expression changes that were due to the laminectomy, samples of contused tissue were compared to laminectomy-only controls. We took advantage of four different, complementary methods of data analysis to detect differentially expressed genes. We have identified functional groups of genes that are differentially regulated in our model, including those associated with apoptosis, cell cycle, inflammation, and cholesterol metabolism. Our analysis has led to the identification of novel potential therapeutic targets within each group of genes that is discussed.     

Serotonin and/or an excitatory amino acid in the medial medulla mediates stimulation-produced antinociception from the lateral hypothalamus in the rat

Several lines of evidence have demonstrated a role for the lateral hypothalamus (LH) in an endogenous system of descending inhibition. Descending inhibition from the LH relies, at least in part, on a relay(s) in the midbrain and/or medulla. The medullary nucleus raphe magnus (NRM) serves as one such relay. The present study, in rats lightly anesthetized with pentobarbital, was undertaken to systematically examine the transmitter(s) in the medial medulla mediating descending inhibition of the nociceptive tail flick (TF) reflex produced by focal electrical stimulation in the LH. The microinjection of pharmacologic receptor antagonists (5 μg) into the NRM revealed that the glutamate receptor antagonists, γ- -glutamylglycine and 2-amino-5-phosphonovalerate produced the largest increases in stimulation thresholds in the LH for inhibition of the TF reflex (107.6% and 102.6%, respectively). Methysergide, a serotonin receptor antagonist, also produced a significant increase (81.5%) in the stimulation threshold in the LH for inhibition of the TF reflex. The opioid receptor antagonist, naloxone, however, was without effect, producing only a 4.0% increase in the LH stimulation threshold. These results suggest that serotonin and/or an excitatory amino acid are transmitters at the bulbar relay in the medial medulla mediating descending inhibition of the TF reflex produced by focal electrical stimulation in the LH.     

Laparoscopic liver resection using a radiofrequency dissector. Initial experience

Laparoscopic liver surgery, especially when resective, requires both the skill of an expert laparoscopist and the experience of a liver surgeon. The aims of the study were to assess the feasibility of minor laparoscopic liver resection by means of a radiofrequency dissector and to evaluate the laparoscopic approach. From January 1993 to November 2002 we carried out 7 laparoscopic liver resections (3 men, 4 women), 5 of which for benign diseases and 2 for metastases from colorectal cancer. In 4 of the above resections we used an argon coagulator, while the last 3 were performed using a radiofrequency instrument. We had no perioperative or postoperative complications in this small series of patients. The mean perioperative blood loss was 120 ml (range: 80-200) and the procedure took about 90 minutes on average (range: 80-110). The mean hospital stay was 4 days and pain was adequately controlled by administering 2 ml of Toradol twice daily. We believe that the advantages of the laparoscopic technique together with the efficacy of the radiofrequency instrument in liver surgery will lead to a more widespread use of this procedure and extension of its use to include the safe execution of both minor and major resections.     

A new class of potent vascular endothelial growth factor receptor tyrosine kinase inhibitors: structure-activity relationships for a series of 9-alkoxymethyl-12-(3-hydroxypropyl)indeno[2,1-a]pyrrolo[3,4-c]carbazole-5-ones and the identification of CEP-5214 and its dimethylglycine ester prodrug clinical candidate CEP-7055

A series of potent vascular endothelial growth factor R2 (VEGF-R2) tyrosine kinase inhibitors from a new indenopyrrolocarbazole template is reported. The structure-activity relationships for a series of 9-alkoxymethyl-12-(3-hydroxypropyl)indeno[2,1-a]pyrrolo[3,4-c]carbazole-5-ones revealed an optimal R9 substitution with ethoxymethyl 19 (VEGF-R2 IC(50) = 4 nM) and isopropoxymethyl 21 (VEGF-R2 IC(50) = 8 nM) being the most potent inhibitors in the series. The VEGF-R2 activity was reduced appreciably by increasing the size of the R9 alkoxy group or by alpha-methyl branching adjacent to the ring. The combined R9 alkoxymethyl and N12 hydroxypropyl substitutions were required for potent VEGF-R2 activity, and the corresponding thioether analogues were weaker than their ether counterparts. Compound 21 (R9 isopropoxymethyl, CEP-5214) was identified as a potent, low-nanomolar pan inhibitor of human VEGF-R tyrosine kinases, displaying IC(50) values of 16, 8, and 4 nM for VEGF-R1/FLT-1, VEGF-R2/KDR, and VEGF-R3/FLT-4, respectively, with cellular activity equivalent to the isolated enzyme activity. Compound 21 exhibited good selectivity against numerous tyrosine and serine/threonine kinases including PKC, Tie2, TrkA, CDK1, p38, JNK, and IRK. To increase water solubility and oral bioavailability, the N,N-dimethylglycine ester 40 was prepared. In pharmacokinetic studies in mice and rats, increased plasma levels of 21 were observed after oral administration of 40. Compound 21 demonstrated significant in vivo antitumor activity in numerous tumor models and was advanced into phase I clinical trials as the water-soluble N,N-dimethylglycine ester prodrug 40 (CEP-7055).     

Pharmacogenetic determinants of immediate and delayed reactions of drug hypersensitivity

Drug allergy refers to a hypersensitivity reaction for which either an IgE or T-cell-mediated mechanism is demonstrated. The recognition of the drug by B and T cells is influenced by variants of HLA genes. The genetic factors involved in IgE-mediated mechanisms have been studied mainly in beta-lactam reactions, and they appear to be related to human leukocyte antigen presentation (HLA A2 and DRw52), TNFA -308G>A, class switching to IgE by B cells (variants of IL-13 and of IL-4RA), and expression of IgE receptors on target cells (variant of the FcepsilonRIbeta gene). Delayed T-cell-mediated reactions are also associated with HLA alleles. Studies have reported an association of HLA-B*1502 and HLA-B*5801 in patients with the Stevens-Johnson syndrome or toxic epidermal necrolysis provoked by carbamazepine, as well as of HLA-B*5701 with abacavir hypersensitivity. HLA-B*5701 seems to be a strong predictor in whites, but not in Hispanics or Africans. Carbamazepine hypersensitivity is also influenced by gene variants of cytochrome P450 enzymes on the generation of reactive metabolites, while CYP2C9*2 and CYP2C9*3 polymorphisms influence the bioactivation of sulfamethoxazole in prohapten. Pharmacogenetic studies on aspirin hypersensitivity have identified distinct types of predictors, such as HLA genotypes, a polymorphism in the promoter of the FcepsilonRIalpha gene, and variants in genes of enzymes from the arachidonic acid pathway. In the future, identification of genetic predictors will benefit from genomewide association studies that also take ethnic differences into account. Ideally, predictors will help to prevent adverse reactions, as suggested by a recent study on the effectiveness of prospective HLA-B*5701 screening to prevent hypersensitivity reactions to abacavir in HIV patients.     

Vaccine Hesitancy and Betrayal Aversion

Annals of Biomedical Engineering - The determinants of vaccine hesitancy remain complex and context specific. Betrayal aversion occurs when an individual is hesitant to risk being betrayed in an...     

High‐Frequency Color Doppler Sonography of Bullous Pemphigoid

Bullous pemphigoid is the most frequent autoimmune‐mediated blistering skin disease, belonging to the group of subepidermal bullae. We performed high‐frequency color Doppler sonography in 3 cases of bullous pemphigoid, in bullous and adjacent non‐bullous skin, which showed homogeneous sonographic findings. Subepidermal cystic structures with dermal hypoechogenicity were observed in bullous skin. In nonbullous skin, the dermis showed hypoechogenicity compared to normal skin. Color Doppler signals were increased in both areas. These findings correlate histologically with subepidermal bullae and dermal inflammatory infiltrates.     

Synapse formation on neurons born in the adult hippocampus

Although new and functional neurons are produced in the adult brain, little is known about how they integrate into mature networks. Here we explored the mechanisms of synaptogenesis on neurons born in the adult mouse hippocampus using confocal microscopy, electron microscopy and live imaging. We report that new neurons, similar to mature granule neurons, were contacted by axosomatic, axodendritic and axospinous synapses. Consistent with their putative role in synaptogenesis, dendritic filopodia were more abundant during the early stages of maturation and, when analyzed in three dimensions, the tips of all filopodia were found within 200 nm of preexisting boutons that already synapsed on other neurons. Furthermore, dendritic spines primarily synapsed on multiple-synapse boutons, suggesting that initial contacts were preferentially made with preexisting boutons already involved in a synapse. The connectivity of new neurons continued to change until at least 2 months, long after the formation of the first dendritic protrusions.