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Biomedical subjects

C R Humphreys

Publications and source records attributed to C R Humphreys.

8 recordsLinked to original sources
PubMed1998

Effects of Sl nerve-root lengthening on tibial nerve F-wave latency in healthy subjects.

OBJECTIVE: To determine if lengthening the tibial portion of the sciatic nerve in healthy patients significantly alters F-wave latency. SUBJECTS: Ten volunteer students (6 men and 4 women). SETTING: Chiropractic college clinic. METHODS: F-wave latency was measured bilaterally in the supine position and supine in 40-50 degrees of passive hip flexion. Block randomization determined the test sequence. Supramaximal surface stimulation was delivered over the tibial nerve using transcutaneous electrical stimulation. The nerve was stimulated no more than 30 times at a rate of 1 Hz for 0.5 ms to get 16 F-wave latencies. The paired t test was used to determine mean difference between neutral and flexion. RESULTS: The F-wave latency was found to be longer in hip flexion (average 46.12 +/- 3.80 ms) than neutral (average 45.12 +/- 3.33 ms). CONCLUSION: Positioning a patient to optimize nerve lengthening and elicit symptoms may reveal occult dysfunction in electrodiagnostic examination.

Adult↗
PubMed1993

The Hmax/Mmax ratio as an outcome measure for acute low back pain.

OBJECTIVE: To evaluate the use of the Hmax/Mmax (H/M) ratio as an outcome measure for acute low back pain and to determine the change of this ratio in acute low back pain patients treated with spinal manipulation. DESIGN: Randomized clinical trial. SETTING: Chiropractic college teaching clinic. PATIENTS: Thirty-six patients with acute low back pain (pain of less than 2 wk duration) were referred by clinicians of the teaching clinic. Eligibility criteria for inclusion into the study consisted of the following: a score of eight or more on the Oswestry questionnaire, 33 mm or greater on a 100-mm visual analog scale, no involvement in litigation related to the low back pain complaint, patient not pregnant and no physical or electrodiagnostic signs of nerve root entrapment. INTERVENTIONS: The patients were randomly assigned to either a treatment or control group. The treatment group (n = 17) received treatment deemed appropriate by the clinician as long as it included a side-lying manipulation to the appropriate level. The control group (n = 19) received detuned ultrasound, application of a cold pack and 15-30 sec of very gentle soft tissue massage. Patients were treated three to five times over a period of 10 days and were subsequently reevaluated. MEASUREMENTS: The Hmax/Mmax ratio was calculated from the results of electrodiagnostic testing of the posterior tibial nerve. Extension/flexion ratio of the trunk musculature, Oswestry score and Visual Analog Scale score were also measured. MAIN RESULTS: The mean difference between H/M ratios pre- and postintervention for the group treated by chiropractic methods was -0.101 on the left and -0.117 on the right. The mean difference for the control group was 0.038 on the left and 0.036 on the right. Although not statistically significant, trends suggest that at the time of final assessment, the group receiving chiropractic care had improved more than the control group. CONCLUSIONS: The H/M ratio was found to be within normal limits in subjects with acute low back pain. The H/M ratio showed greater change in the group which received spinal manipulation, but the change was subtle. The results indicate that the H/M ratio may be of limited value in clinical practice.

Adult↗
PubMed1989

Sensitivity study of H-reflex alterations in idiopathic low back pain patients vs. a healthy population.

Twenty-seven male and 12 female healthy volunteers were tested twice with 2-7 days separation. Hoffman (H) reflexes and muscle (M) activation waves were obtained from the posterior tibial nerves bilaterally. Results were compared to those obtained from patients presenting with a complaint of low back and/or leg pain, without compressive neuropathy. M, F, H latencies and H/Mmax ratio were recorded. H/M ratio and latency comparisons were not significantly different in the control group left to right or test to test. For the low back pain group, 10-14 days following the initial evaluation, each subject returned for a follow-up test. During the interim, the patient was followed conservatively using manipulation and home care. Analysis of variance (ANOVA) testing of ratio values demonstrated a difference in overall mean values (p greater than 0.001) for comparisons between the control (mean = 0.367), pretest (mean = 0.695), and posttest (mean = 0.558) values. Sensitivity in discriminating acute low back pain subjects from healthy controls was tested by determining the distance between mean H/M values for the probability curves of each population, with an arbitrary cutoff value of 0.6 as the upper limit normal. Sensitivity distance was 2.29 with a likelihood ratio of 3.04. This suggests that an H/Mmax ratio greater than or equal to 0.6 will correctly identify two of three patients with idiopathic low back pain.

Adult↗
PubMed1989

Bunyaviridae. Serological relationships.

The family Bunyaviridae comprises 5 genera of lipid-enveloped viruses with trisegmented RNA genomes. One of the genera, Bunyavirus, comprises over a quarter of the known arboviruses. The members of the Hantavirus genus are apparently the exception in that they are not arthropod-borne. The genera are sorted largely on serological grounds. The Nairoviruses, in addition to the presence of the physical marker of a higher molecular weight nucleoprotein, include Congo-Crimean haemorrhagic fever, an apparently isotypic virus of wide distribution.

Animals↗
PubMed1987

Patient monitoring in the conservative management of cervical radiculopathy.

With increasing frequency, concern is being raised by nonmanipulating health professionals over the use of manual procedures in the cervical spine. With respect to treatment of radicular syndromes secondary to discogenic spondylosis, the potential for occasional iatrogenic complications must be an "a priori" consideration. Illustrated with the data from case presentation, conservative therapeutic management utilizing electrodiagnostic monitoring in questionable cases is discussed. Anecdotal improvement in median nerve F-wave function following conservative treatment including spinal manipulation is presented.

Cervical Vertebrae↗
PubMedDate not supplied

Oral chemotherapy of fatal B virus (herpesvirus simiae) infection.

Acyclovir and ganciclovir, which were only about 10-fold less effective against B virus than herpes simplex virus type 1 in VERO cells, were tested in vivo in B virus-infected rabbits. Untreated control rabbits became paralysed from 8 days and died from 10 days. Oral acyclovir at a dose rate of 500 mg/kg/day for 21 days prevented death; acyclovir prevented disease at 700 mg/kg/day. In B virus-infected humans such a high dose of acyclovir could not be given by mouth. Nevertheless, high dose oral acyclovir is suggested for immediate prophylaxis when monkey handlers have been exposed to potentially fatal B virus infection. Should signs or symptoms of disease occur then high dose intravenous acyclovir has been recommended. Since ganciclovir was found to be more effective than acyclovir, intravenous ganciclovir might be preferred for the treatment of established infection.

Administration, Oral↗
PubMedDate not supplied

Electrodiagnostic testing in back and extremity pain.

OBJECTIVE: The usefulness of electrodiagnostic testing by the primary care provider is shown in two cases of suspected compression-type neural lesions of the lumbar spine. CLINICAL FEATURES: A 54-yr-old female with acute lumbar spine pain that radiated into the hip and a 26-yr-old male with sharp gluteal pain that radiated into the thigh and ankle were admitted into an inpatient care facility for intensive therapy. Plain film radiographs were obtained initially. In addition, electrodiagnostic testing was performed to evaluate the L5 and S1 nerve roots, which suggested compressive-type lesions. Non-enhanced CT of the lumbar spine was performed and revealed central disk herniation or protrusion in each case. INTERVENTION AND OUTCOME: One patient exhibiting central compression signs of bladder dysfunction was referred for medical intervention. The remaining patient received flexion-distraction type of chiropractic manipulation with physiologic therapeutics and was discharged to outpatient care after 16 days. CONCLUSIONS: Electrodiagnostic testing can provide the primary care provider the data needed to make an informed decision regarding advanced imaging studies and to institute appropriate therapy or to intelligently refer a patient for follow-up.

Adult↗