C57BL/6 substrain differences in formalin-induced pain-like behavioral responses

Substantial evidence from preclinical models of pain suggests that basal and noxious nociceptive sensitivity, as well as antinociceptive responses to drugs, show significant heritability. Individual differences to these responses have been observed across species from rodents to humans. The use of closely related C57BL/6 inbred mouse substrains can facilitate gene mapping of acute nociceptive behaviors in preclinical pain models. In this study, we investigated behavioral differences between C57BL/6 J (B6 J) and C57BL/6 N (B6 N) substrains in the formalin test, a widely used tonic inflammatory pain model, using a battery of pain-related phenotypes, including reflexive tests, nesting, voluntary wheel running, sucrose preference and anxiety-like behavior in the light/dark test at two different time points (1-h and 24-h). Our results show that these substrains did not differ in reflexive thermal and mechanical responses at the 1-h time point. However, B6 N substrain mice showed increased sensitivity to spontaneous pain-like behaviors. In addition, B6 N substrain continued to show higher levels of mechanical hypersensitivity compared to controls at 24-h. indicating that mechanical hypersensitivity is a more persistent pain-related phenotype induced by formalin. Finally, no sex differences were observed in our outcome measures. Our results provide a comprehensive behavioral testing paradigm in response to an inflammatory agent for future mouse genetic studies in pain.

Transient ischaemic attacks due to a pulsating mass in the neck produced after incision and drainage of parapharyngeal abscess

Carotid endarterectomy is the most commonly performed vascular surgical procedure. One of the complications of carotid endarterectomy is Pseudoaneurysm of the carotid artery frequently managed by endo-vascular technique. Pseudoaneurysm caused by other aetiological factors is rare entity. Penetrating trauma and neck surgery are known but very rare causes of pseudo aneurysm of the carotid artery. We have successfully managed a case of carotid artery pseudoaneurysm caused by incision and drainage of parapharyngeal abscess. This surgery also leads to the palsy of right vagus nerve causing complete hoarseness of voice. The patient presented with Transit Ischaemic Attacks (TIA) and amurosis fugos. Resection of aneurysm and reconstruction of right carotid artery lead to complete recovery. Vocal cord palsy was managed by Vox implant injection leading to full recovery.

Immunolocalization of the heterotrimeric kinesin-related protein KRP(85/95) in the mitotic apparatus of sea urchin embryos

We have used monoclonal antibodies to perform confocal light microscopic immunolocalization of KRP(85/95), a heterotrimeric plus-end-directed microtubule motor protein, in dividing cells of sea urchin embryos. Embryos were stained during the first division cycle, and dissociated blastomeres were stained at the 32- to 64-cell stages. Double labeling of the dividing cells with anti-tubulin and anti-KRP(85/95) showed a clear concentration of the motor protein in the mitotic apparatus; KRP(85/95) appeared to associate with pericentriolar regions during prophase, with kinetochore-to-pole microtubules during metaphase, and, in a striking fashion, with the spindle interzone during anaphase. KRP(85/95) began to accumulate in the interzone immediately following chromosome separation and the area of concentration expanded with the lengthening of the interzonal region during anaphase. During telophase KRP(85/95) appeared to disperse with the establishment of the cleavage furrow and did not concentrate in the midbody. KRP(85/95) staining in the mitotic apparatus was punctate and detergent-sensitive, suggesting an association with membranous vesicles, but unlike kinesin, KRP(85/95) did not appear to codistribute with calsequestrin-containing endoplasmic reticulum. Finally, KRP(85/95) appears to be present in dividing blastomeres up to at least the blastula stage, but, unlike kinesin, it is not expressed in terminally differentiated, nonmitotic coelomocytes of the adult animal. These results suggest that the expression and targeting of KRP(85/95) and kinesin differ and that KRP(85/95) may play a role in vesicle transport during embryonic cell division.

Direct association of pp40/I kappa B beta with rel/NF-kappa B transcription factors: role of ankyrin repeats in the inhibition of DNA binding activity

To understand the mechanism by which pp40/I kappa B beta inhibits DNA binding activity of the rel/NF-kappa B family of transcription factors, we have investigated the role of ankyrin repeats on the biological function of pp40 by deleting or mutating conserved residues. We show that (i) ankyrin repeats alone are not sufficient to manifest biological activity but require the C-terminal region of the pp40 protein; (ii) four out of the five ankyrin repeats are essential for inhibiting the DNA binding activity; (iii) pp40 mutants that do not inhibit DNA binding of rel protein also do not associate with rel; (iv) although pp40 can associate with the p65 and p50 subunits of NF-kappa B, pp40 inhibits the DNA binding activity of only the p50-p65 heterodimer and the p65 homodimer; and (v) pp40 inhibits the transcription of genes linked to kappa B site; however, mutants that do not affect DNA binding have no effect. We propose that the ankyrin repeats and the C-terminal region of pp40 form a structure that associates with the rel homology domain to inhibit DNA binding activity.

Transformation by FosB requires a trans-activation domain missing in FosB2 that can be substituted by heterologous activation domains

Two functionally distinct proteins derived from the FosB gene by alternative splicing have recently been described. FosB protein transforms fibroblasts efficiently, whereas FosB2 protein, a carboxy-terminally truncated form of FosB, does not, despite the fact that both proteins can participate in high-affinity, sequence-specific DNA binding as part of a heterodimeric complex with c-Jun protein. We show here that the functional difference between these proteins is the result of the presence of a potent proline-rich transcriptional activation domain in the carboxy-terminal amino acids unique to FosB. This conclusion is supported by three lines of evidence: (1) Mutations in the carboxy-terminal region of FosB that impair transcriptional activation also reduce transforming potential, despite the fact that DNA binding as part of a complex with c-Jun is not affected; (2) the carboxy-terminal region unique to FosB functions as an activation domain when fused to the DNA-binding domain of GAL4; and (3) transforming potential can be conferred on FosB2 by fusing any of several different well-characterized trans-activation domains. These results identify an additional functional requirement for transformation by Fos proteins and have implications for the mechanism(s) of mitogenic signaling by the AP-1 transcription complex.

CREB represses transcription of fos promoter: role of phosphorylation

We have studied the regulation of protooncogene fos following serum induction. We show that un- or hypo-phosphorylated form of transcription factor cyclic AMP response element binding (CREB) protein represses the transcription of fos promoter. The negative regulation by CREB is alleviated if it is phosphorylated at serine 133 by the catalytic subunit of protein kinase A (PKA). A DNA binding mutant of CREB is unable to suppress transcription of the fos promoter. However, mutation in the cyclic AMP responsive element (CRE) at -60 or AP-1 binding site at -290, known to bind to CREB, does not appear to be involved in repression. Serum induction of dyad symmetry element (DSE) linked reporter gene is also repressed by unmodified CREB, which can be relieved following phosphorylation by PKA. We propose that posttranslational modification of CREB regulates serum inducibility of fos promoter.

Phosphorylation of the C terminus of Fos protein is required for transcriptional transrepression of the c-fos promoter

Proto-oncogene fos encodes a nuclear phosphoprotein of 380 amino acids that can modulate the transcription of other genes either by transactivation or by transrepression. The v-Fos protein (381 amino acids) shares the first 332 amino acids with the c-Fos protein (with five single amino-acid changes), but differs at the C terminus. We have previously reported that the c-Fos protein undergoes more extensive post-translational modification than v-Fos (refs 9, 10). The major modification of the c-Fos protein involves serine phosphoesterification of sites in the extreme C terminus. We therefore argued that modification of the C-terminal region of the c-Fos protein may be involved in its ability to transrepress transcription without compromising its ability to transactivate other genes. Here we show that mutant c-Fos protein which is hypophosphorylated at its C terminus is unable to repress transcription of the c-fos promoter following induction with serum or tetraphorbol acetate. The C-terminal phosphorylation-deficient mutant is, however, fully competent to activate transcription of promoters containing a phorbol response element. The requirement for phosphorylation can be offset by the introduction of a net negative charge in the C terminus of the Fos protein.