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Biomedical subjects

R G Gordon

Publications and source records attributed to R G Gordon.

9 recordsLinked to original sources
PubMed2000

Interaction of HIV-1 Tat with Puralpha in nuclei of human glial cells: characterization of RNA-mediated protein-protein binding.

A complex between the Tat protein, encoded by human immunodeficiency virus type 1 (HIV-1), and the cellular protein, Puralpha, has been implicated in activation of the late promoter of JC virus (JCV) and in enhancement of JCV DNA replication. JCV is the causative agent of progressive multifocal leukoencephalopathy (PML), an acquired immunodeficiency syndrome (AIDS) opportunistic infection of the brain. Puralpha also binds the HIV-1 TAR RNA element and activates HIV-1 transcription, suggesting a role for RNA binding in the action of this protein. Using immunoelectron microscopy, we find that in human glial cells expressing both proteins, Tat and Puralpha are colocalized in extranucleolar chromatin structural elements. The colocalized Puralpha and Tat are nearly exclusively nuclear, although individual proteins can be seen in both nucleus and cytoplasm, suggesting a preferential tropism of the complex for the nucleus. Analysis of the interaction between purified proteins indicates that the Tat-Puralpha interaction is strongly enhanced by the presence of RNA. Tat amino acids from 37-48 are essential for Tat binding. Residues 49-72, including the TAR RNA-binding domain, are critical for binding to Puralpha, while Cys(22), in the Tat transactivation domain, is responsible for an important global effect. Puralpha repeat II domains are involved in the interaction, and a polypeptide based on one such sequence inhibits binding. After RNase treatment of Puralpha enhancement of Tat binding can be partially restored by addition of a single-stranded JCV DNA PUR element, to which Tat does not bind. The results indicate that the Tat-Puralpha interaction is direct, rather than through an RNA link, and that RNA binding configures Puralpha for optimal interaction with Tat.

Biological Transport↗
PubMed1992

Intraoperative somatosensory evoked potential monitoring of pelvic and acetabular fractures.

The efficacy of intraoperative somatosensory evoked potential (SSEP) monitoring was evaluated in the surgical management of 82 patients with pelvic and acetabular fractures. The injuries consisted of 45 acetabular fractures, 30 pelvic ring disruptions, and seven combined injuries. Preoperative neurological deficits were recorded in 34% of the study group (29% of those with an acetabular fracture and 47% of those with a pelvic ring injury). Three patients sustained an iatrogenic sciatic nerve injury during the study period (all of which were documented in the first 40 cases). Two patients sustained an exacerbation of an existing sciatic nerve injury. In the group of pelvic fractures, hazardous parts of the exposure, reduction, and fixation were identified by the SSEP monitoring. Removal of the provocative stimulus by the surgeon led to reversal of the SSEP abnormalities, and none of this group of patients sustained an iatrogenic injury. When the intraoperative SSEP changes were noted during an acetabular fracture fixation, immediate attempts were made to relieve the excessive tension on the sciatic nerve by replacing or removing a retractor, flexing the knee, extending the hip, or dividing the femoral insertion of the gluteus maximus. None of the SSEP changes were associated with the lacerative injury to the sciatic nerve. For the method to be clinically effective in reducing the incidence of neurological deficit, even subtle changes in the SSEP tracing must be recognized immediately by the neurophysiologist so that a corresponding corrective measure can be rapidly undertaken by the surgeon to remove the offending stimulus.

Acetabulum↗
PubMed1991

Ankle arthrodesis with an anterior tension plate.

The incidence of complications associated with arthrodesis of the ankle has remained high, especially in wound complications and infections. A new method to achieve arthrodesis of the ankle that utilizes an anterior surgical approach and an anterior tension plate was assessed in 17 patients. This method transforms the potentially deforming force of the tendoachilles into a compressive and corrective force and facilitates realignment of the ankle in all planes. Also, dissection and subperiosteal elevation is minimized while soft tissue coverage of the hardware is maximized. Whereas the predominant preoperative diagnosis was posttraumatic degenerative joint disease, others included failed ankle arthroplasty, failed arthrodesis, and a fixed equinus deformity. A solid arthrodesis was achieved in 82% of the patients. Although complications occurred and two patients required reoperations, there were no problems with respect to wound healing or infection, which is a marked contrast to other series. This technique is recommended as a simple, safe, and effective method to achieve an arthrodesis of the ankle joint.

Adult↗
PubMed1987

Nalbuphine: a supplement to isoflurane and enflurane anaesthesia.

A retrospective study was carried out to review the intra-operative use of nalbuphine at the average dose of 1.5 mg/kg as a supplement to isoflurane and enflurane in balanced anaesthesia in 108 surgical patients. Intra-operative cardiovascular stability and the quality of emergence were examined. The amount of halogenated anaesthetic used was compared to the theoretical amount that would have been needed in the absence of nalbuphine. In 90% to 95% of patients, blood pressures remained within 20% of baseline for the duration of anaesthesia. At emergence, 80% of patients had no pain. Nalbuphine appeared to reduce halogenated anaesthetic requirements by approximately 50%. These promising results for the intraoperative use of nalbuphine need to be confirmed by controlled prospective studies.

Adult↗
PubMedDate not supplied

New method for objectively assessing lameness in broiler chickens.

A new method for assessing the severity of lameness in broiler chickens is described. The length of time that birds remained standing in shallow water was measured and the results were compared with the results of conventional gait scoring. There was a highly significant (P < 0.001) relationship between the birds' gait scores and their latency to lie down. Over 750 broilers aged between 32 and 45 days of age were tested in commercial houses and whereas nearly all the sound birds were able to stand for at least 15 minutes, the majority of lame birds lay down within five minutes.

Animals↗