Perioperative gabapentin reduces 24 h opioid consumption and improves in-hospital rehabilitation but not post-discharge outcomes after total knee arthroplasty with peripheral nerve block.

BACKGROUND: This study was designed to determine whether a 4 day perioperative regimen of gabapentin added to celecoxib improves in-hospital rehabilitation and physical function on postoperative day 4 and 6 weeks and 3 months after total knee arthroplasty (TKA). METHODS: After Research Ethics Board approval and informed consent, 212 patients were enrolled in a randomized, double-blinded, placebo-controlled study. Two hours before surgery, patients received celecoxib 400 mg p.o. and were randomly assigned to receive either gabapentin 600 mg or placebo p.o. Two hours later, patients received femoral, sciatic nerve blocks, and spinal anaesthesia. After operation, patients received gabapentin 200 mg or placebo three times per day (TID) for 4 days. All patients also received celecoxib 200 mg q12 h for 72 h and i.v. patient-controlled analgesia for 24 h. Pain and function were assessed at baseline, during hospitalization, on postoperative day 4 (POD4), and 6 weeks and 3 months after surgery. RESULTS: The gabapentin group used less morphine in the first 24 h after surgery [G=38.3 (29.5 mg), P=48.2 (29.4 mg)] (P<0.0125) and had increased knee range of motion compared with the placebo group in-hospital (P<0.05). There were no differences between groups in favour of the gabapentin group for pain or physical function on POD 4 [95% confidence interval (CI): pain: -1.4, 0.5; function: -6.3, 2.0], 6 weeks (95% CI: pain: 0.1, 1.9; function: -0.2, 6.5) or 3 months (95% CI: pain: -0.2, 1.7; function: -2.2, 4.3) after TKA. CONCLUSIONS: In the context of celecoxib, spinal anaesthesia, femoral and sciatic nerve blocks, a dose of gabapentin 600 mg before operation followed by 4 days of gabapentin 200 mg TID decreased postoperative analgesic requirements and improved knee range of motion after TKA. Gabapentin provided no improvement in pain or physical function on POD4 and 6 weeks or 3 months after surgery.

Identification of lamina V and VII interneurons presynaptic to adrenal sympathetic preganglionic neurons in rats using a recombinant herpes simplex virus type 1.

Although indirect evidence suggests that the control of sympathetic preganglionic neurons is mediated to a great extent through interneurons, little is known about the location, morphology or neurotransmitter phenotype of such interneurons. This limitation seriously impedes our understanding of spinal synaptic circuits crucial to control of arterial pressure and other visceral functions. We used a highly neurotropic, minimally cytopathic recombinant herpes simplex virus type-1 to study spinal "sympathetic" interneurons labelled by trans-synaptic transport of the virus from the adrenal gland in rats. Approximately 120-320 infected neurons/rat were identified by immunocytochemical detection of the viral antigen. We distinguished between virus-infected preganglionic neurons and infected interneurons by (i) their location within the spinal laminae, (ii) their size and shape and (iii) the presence or absence of immunoreactivity for the acetylcholine-synthesizing enzyme, choline acetyltransferase, a marker of sympathetic preganglionic neurons. Virus-labelled sympathetic preganglionic neurons were found within the known spinal preganglionic nuclei. Non-cholinergic, virus-labelled neurons were located throughout lamina VII and in the ventral portion of lamina V. These putative interneurons were found in the major spinal preganglionic nuclei, usually intermingled with the preganglionic neurons. Sometimes, they were located in clusters separate from the preganglionic neurons. The interneurons were approximately 15 microm in diameter, smaller than the average preganglionic neuron (diameter=25 microm), and had a few fine processes emanating from them. These non-cholinergic interneurons constituted approximately one-half of the population of virus-infected neurons. In summary, with the use of a recombinant herpes simplex virus, we identified a large number of non-cholinergic interneurons close to, or intermingled with, adrenal sympathetic preganglionic neurons. The neurotransmitter phenotype of these neurons remains to be determined but they likely integrate much of the supraspinal and primary afferent inputs to spinal preganglionic neurons that control arterial pressure and other visceral functions.

Combined hippocampal and amygdala lesions block learning of a response-independent form of occasion setting.

This study compared rats with dorsal striatal, ventrolateral prefrontal cortical, and combined lesions of the hippocampus and amygdala to sham controls on a conditional discrimination task in which contextual cues modulated a taste aversion. All groups were able to acquire this occasion setting task. The 2nd experiment functionally minimized the stimulus-response component of the paradigm, creating a "tasteless" form of occasion setting. Rats with pretraining lesions of the hippocampus and amygdala were impaired compared with shams on the acquisition of this tasteless occasion setting task. Rats with posttraining combined lesions did not retain the ability to perform the tasteless occasion setting task learned preoperatively. Rats with selective lesions of either the hippocampus or the amygdala alone were not impaired in the acquisition of the tasteless occasion setting task. The findings suggest that this occasion setting task may be learned by several redundant neural systems.

Sitting prone position for the posterior surgical approach to the spine and posterior fossa.

The sitting prone position is compared with the standard laminectomy prone position and the sitting up position for posterior fossa surgery. We measured central venous pressure and airway pressure with the patient in different positions to determine the comparative efficacy of the sitting prone position. On a linear average, the central venous pressure increased by 6.83 cm H2O and the airway pressure increased by 3.16 cm H2O when the patient was changed from the supine to the standard prone position under general anesthesia; with a change from the standard prone position to the sitting prone position, the central venous pressure decreased by 10.45 cm H2O and the airway pressure decreased by 3.66 cm H2O. However, comparing the sitting prone position for posterior fossa surgery with the sitting up position, there was no statistically significant difference in central venous or airway pressure.

Uterine leiomyosarcoma with intracerebral metastasis: a case report.

A case of a 36-year-old woman with a past history of uterine leiomyosarcoma and an intracerebral metastasis is reported. The patient presented with a 24-hour history of severe headache with coma, and the CT findings were consistent with a metastatic lesion. Pathological examination of the operative specimen showed features of a leiomyosarcoma. Uterine leiomyosarcoma is an uncommon tumor and metastasis to the brain is rare.

An abnormal pattern of amniotic fluid microvillar enzymes signalling fetal cystic fibrosis.

We have observed seven pregnancies at risk for fetal cystic fibrosis where second-trimester amniotic fluid microvillar enzyme activities presented an unusual pattern. Low gamma-glutamyltranspeptidase and borderline alpha-glucosidase values were associated with normal aminopeptidase M and intestinal alkaline phosphatase values. All seven pregnancies went to term; five of the seven infants were affected with cystic fibrosis.

Prenatal diagnosis of cystic fibrosis by microvillar enzyme assay on a sequence of 258 pregnancies.

Prenatal diagnosis of cystic fibrosis by microvillar enzyme assay on amniotic fluid supernatant has been carried out on 258 sequential pregnancies with a 1 in 4 recurrence risk, all with known outcome. In general the three enzymes evaluated, gamma-glutamyltranspeptidase, aminopeptidase M and the intestinal isoenzyme of alkaline phosphatase, showed a high degree of concordance. However, there were two unusual patterns of microvillar enzyme activity; in seven cases a low gamma-glutamyltranspeptidase activity was associated with elevated values of intestinal alkaline phosphatase, and in ten cases there were isolated low values of intestinal alkaline phosphatase. The former pattern was found to be associated with cystic fibrosis in five cases, while the latter was associated with a normal outcome in all ten cases. A retrospective analysis of enzyme values suggested that the optimal system for minimizing false positives and false negatives was to define foetal cystic fibrosis as a sample where two of the three microvillar enzymes were below a cut-off of half the median value for the gestational week. If such scoring were applied to the cases where conventional microvillar enzyme patterns were observed, the false positive rate was 2.3% and the false negative rate 4.4% between 17 and 20 weeks of gestation.

Complex partial seizures associated with a temporomandibular joint defect.

A case of a 32-year-old man is reported with complex partial seizures secondary to a right inferior temporal epileptic focus immediately overlying an abnormality of the temporomandibular joint, with a defect in the middle temporal fossa that allowed the mandibular condyle to contuse the temporal lobe.

Identification of a putative cellular receptor for the lentivirus visna virus.

One mechanism by which viral tropism may be controlled is by the expression of a specific virus receptor on the cell surface. This paper reports the identification of a putative cellular receptor for visna virus, the prototype virus of the family Lentiviridae. Using a virus overlay protein blot assay we identified a group of polypeptides of apparent Mr 30K to 33K which interacts with visna virus and is present on permissive but not non-permissive cells. A rat polyclonal anti-ovine major histocompatibility complex (MHC) class II antigen (Ag) serum raised to immunopurified MHC class II Ag, but not preimmune serum, blocked the interaction of visna virus with these polypeptides. In an ELISA, immunopurified MHC class II Ag bound to visna virus but not to bovine parainfluenza 3 virus. Preincubation of visna virus with immunopurified soluble MHC class II Ag resulted in a marked decrease in virus-induced syncytium formation, i.e. preincubation with class II Ag inhibited infection with visna virus, but we have been unable to inhibit infection using class II Ag-specific antisera. These results suggest that ovine MHC class II Ag acts as a component of a cellular receptor for visna virus. This is of particular interest owing to the close similarities between visna virus and human immunodeficiency virus (HIV), and the relationship between MHC class II and CD4, the cellular receptor for HIV. It is also of relevance to recent reports that a growing number of viruses utilize polypeptides of the Ig supergene family as receptors.