Biomedical subjects

K L McDermott

Publications and source records attributed to K L McDermott.

4 recordsLinked to original sources

PubMed1999

Effects of smoking and maturation on long-term maintenance of lumbar spinal fusion success.

This is a follow-up study of a multicenter, randomized, placebo-controlled clinical trial conducted in accordance with the condition for Food and Drug Administration approval for pulsed electromagnetic fields. The purpose of this study was to evaluate the long-term efficacy and safety of pulsed electromagnetic fields for spinal fusion. An earlier clinical trial study was conducted to evaluate the efficacy of Pulsed Electromagnetic Fields to enhance fusion success at one year follow-up. In the original study, 195 patients undergoing interbody fusion were enrolled. Of the 195 patients, 98 were in the active group and 97 were in the placebo group. Study results showed a 92% successful fusion rate in the active group compared to 68% in the placebo group. For this long-term follow-up study, all patients who had healed in the original study were recalled for a follow-up radiograph. Radiographs were assessed by the attending surgeon for fusion assessment, when possible. The results of this long-term follow-up study showed that there was a reduction in maintenance of the fusion over time by 25%, but that the reduction was unrelated to treatment group and correlated statistically with whether the patient was a smoker.

Adult↗

PubMed1997

Insulin-like growth factor-1 (IGF-1) improves both neurological motor and cognitive outcome following experimental brain injury.

We evaluated the efficacy of insulin-like growth factor-1 (IGF-1) in attenuating neurobehavioral deficits following lateral fluid percussion (FP) brain injury. Male Sprague-Dawley rats (345-425 g, n = 88) were anesthetized and subjected to FP brain injury of moderate severity (2.4-2.9 atm). In Study 1, IGF-1 (1.0 mg/kg, n = 9) or vehicle (n = 14) was administered by subcutaneous injection at 15 min postinjury and similarly at 12-h intervals for 14 days. In animals evaluated daily for 14 days, IGF-1 treatment attenuated motor dysfunction over the 2-week period (P < 0.02). In Study 2, IGF-1 (4 mg/kg/day, n = 8 uninjured, n = 13 injured) or vehicle (n = 8 uninjured, n = 13 injured) was administered for 2 weeks via a subcutaneous pump implanted 15 min postinjury. IGF-1 administration was associated with increased body weight and mild, transient hypoglycemia which was more pronounced in brain-injured animals. At 2 weeks postinjury (P < 0.05), but not at 48 h or 1 week, brain-injured animals receiving IGF-1 showed improved neuromotor function compared with those receiving vehicle. IGF-1 administration also enhanced learning ability (P < 0.03) and memory retention (P < 0.01) in brain-injured animals at 2 weeks postinjury. Taken together, these data suggest that chronic, posttraumatic administration of the trophic factor IGF-1 may be efficacious in ameliorating neurobehavioral dysfunction associated with traumatic brain injury.

Animals↗

PubMed1997

Delayed administration of basic fibroblast growth factor (bFGF) attenuates cognitive dysfunction following parasagittal fluid percussion brain injury in the rat.

The present study evaluates the therapeutic effects of delayed administration of bFGF on cognitive dysfunction and histopathological damage following lateral fluid-percussion (FP) brain injury. Male Sprague-Dawley rats were trained to learn a visuospatial task in a Morris Water Maze (MWM) paradigm and then were anesthetized and subjected to either FP brain injury of moderate severity (2.5-2.8 atm, n = 32) or surgery without brain injury (n = 10). Twenty-four hours postinjury, an infusion cannula connected to a mini-osmotic pump was implanted into the area of maximal cortical injury to continuously infuse either bFGF (2.0 g) or vehicle for 7 days. Treatment with bFGF significantly attenuated posttraumatic memory dysfunction in the MWM at 8 days postinjury when compared to vehicle treatment (p < 0.05). The cortical lesion and significant cell loss in the ipsilateral CA3 region of the hippocampus, produced by FP injury, was not affected by bFGF treatment. However, immunohistochemical evaluation of glial fibrillary acidic protein revealed a trend toward increased astrocytosis in the injured cortex of bFGF-treated animals compared to vehicle-treated animals (p < 0.1). These results indicate that bFGF may be efficacious in attenuating cognitive dysfunction associated with traumatic brain injury.

Analysis of Variance↗

PubMed1982

Fatigue in cat facial mechanoreceptors.

Mechanoreceptor fatigue, the reduction in number of impulses with repeated presentations of the same mechanical stimulus, was studied in facial hairy skin of the cat. We found that the variables that influence the magnitude of fatigue are, in order to importance: stimulus duration, interstimulus interval and stimulus amplitude. We also found that in about 40% of all mechanoreceptors studied, phentolamine, an alpha-noradrenergic antagonist, produced periodic reversal of fatigue and in some cases produced an increase in spontaneous firing.

Animals↗