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Biomedical subjects

M F Nolan

Publications and source records attributed to M F Nolan.

17 recordsLinked to original sources

Patient-controlled analgesia: a method for the controlled self-administration of opioid pain medications.

The purposes of this article are to introduce the reader to patient-controlled analgesia (PCA) and to summarize its use in several selected pain-related conditions. patient-controlled analgesia is a relatively new technique for managing pain in which patients are able to self-administer small doses of opioid analgesic medications when needed. The authors briefly review some of the problems associated with current and previous opioid delivery strategies and highlight the advantages of PCA over these other methods. They then discuss the components of the PCA system and briefly describe how the system is operated and controlled. In this discussion, the authors indicate an appropriate therapeutic goal and suggest knowledge requirements for the effective use of PCA. The authors close with a brief summary of several reports describing the use of PCA in the management of postoperative pain, cancer pain, and pain associated with labor and delivery. Indications and contraindications for use in these conditions are presented. Because physical therapists often play a major role in pain management, it is important for them to be well informed with regard to recent developments in this rapidly developing area of clinical practice.

Analgesia, Patient-Controlled

Conductive differences in electrodes used with transcutaneous electrical nerve stimulation devices.

The purpose of this study was to document conductive differences among commercially available electrodes used with transcutaneous electrical nerve stimulation (TENS) devices. Impedance within a model system involving a human subject was calculated from oscilloscopic tracings of the pulse waveform for each of 25 different electrode types. Impedance values ranged from 1,000 to 7,800 omega Possible reasons for these differences are discussed. The observation that electrodes vary in their impedance and can thereby affect the stimulus applied to the skin raises the question of whether electrode choice might affect the clinical effectiveness of TENS. Attention is drawn to the skin electrodes as a variable that may affect the results of clinical and basic studies involving TENS.

Adult

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Selected problems in the use of transcutaneous electrical nerve stimulation for pain control--an appraisal with proposed solutions. A special communication.

The purposes of this communication are 1) to call attention to several problematic issues related to the use of transcutaneous electrical nerve stimulation for pain control and 2) to consider strategies for correcting existing problems and averting additional problems in the future. Specific problems within two general areas of difficulty are identified, and proposed solutions to these problems are presented. It is hoped that discussion of these issues will encourage comment and debate, bring about further objective and critical evaluation of the effectiveness and value of TENS for pain control, and lead to a clearer understanding of the responsibilities of manufacturers and users of this therapeutic modality.

Consumer Behavior

Transcutaneous electrical nerve stimulation for pain control after spinal fusion with Harrington rods. A clinical report.

During the past two years, we have been using transcutaneous electrical nerve stimulation (TENS) for pain control after spinal fusion with Harrington rods. This report describes our postoperative pain management program and our evaluation of its effectiveness. We examined postoperative pain medication usage and found that patients using TENS received fewer doses of several commonly prescribed pain drugs than did patients not using TENS devices. Difficulties we encountered in evaluating our program are described along with recommendations for other researchers interested in assessing TENS in the management of postoperative pain.

Adolescent

Quantitative measure of cutaneous sensation. Two-point discrimination values for the face and trunk.

This study was performed to assess two-point discrimination ability for skin areas of the face and trunk. Using a compass-type instrument, I determined two-point discrimination values for three areas on the face and eight, nonoverlapping regions of the neck and trunk in a sample of 43 healthy young adult men and women. Mean values for the face ranged from 14.9 mm over the eyebrow to 10.4 mm along the lateral aspect of the mandible. Values for the neck and trunk ranged from 35.2 mm for skin of the lateral neck to 55.4 mm for the region immediately lateral to the C7 spinous process. I also found interindividual variation in two-point discrimination ability for a given skin area. Except for skin overlying the body of the mandible, where values for women were lower than those measured in men, no significant differences in discrimination ability were found between men and women. Although assessment of two-point discrimination is useful in the clinical evaluation of certain types of patients, the existence of intraindividual and interindividual differences suggests that therapists must interpret the results of these tests with caution.

Adolescent

Primary afferent projections to the sacral secondary visceral gray: a quantitative electron microscopic examination in the cat.

Afferent input to the sacral secondary visceral gray matter was studied by quantitatively assessing synaptic degeneration that follows ipsilateral sacral dorsal rhizotomy. Five days after the lesions, slightly more than 25% of the synaptic contacts showed degenerative changes. The majority of the reactive synapses contained clear spherical vesicles (S type). Boutons containing dense core vesicles (GS type) also showed degenerative changes, and together with S boutons constituted more than 96% of the reactive terminals. Degenerating S type synapses were found only on dendrites whereas GS boutons were observed on both cell bodies and dendrites. Further examination revealed that although there were more S than GS synapses in the nucleus, the percentage of GS terminals affected was greater than that for S type boutons. These results demonstrate a direct primary afferent input to the sacral secondary visceral gray matter utilizing chiefly two different synaptic types.

Afferent Pathways

Limits of two-point discrimination ability in the lower limb in young adult men and women.

The purpose of this study was to determine the limits of two-point discrimination ability in the lower limb in a sample of healthy, young adult men and women. Eleven different areas of skin were tested with a commercially available compass-type instrument to determine the shortest distance at which two simultaneously applied, nonpainful, light-touch stimuli could be perceived. Mean two-point discrimination values in the lower limb ranged from 43.6 mm for skin overlying the medial surface of the leg to 6.6 mm on the plantar surface of the tip of the great toe. The results also demonstrated interindividual variation in two-point discrimination for a given area of skin. In the majority of skin areas tested, mean values obtained from men and women were essentially the same. In several of the test areas, however, women were significantly better than men in their two-point discrimination ability. The observed intraindividual and interindividual variation suggests that although two-point testing is a useful clinical tool, caution is necessary when interpreting the results from patients with alterations in cutaneous sensibility.

Adult

Two-point discrimination assessment in the upper limb in young adult men and women.

Two-point discrimination sensitivity in the upper limb was evaluated in a sample of healthy, young adult men and women. A commercially available compass-type instrument was used to determine limits of two-point discrimination sensitivity in 11 skin areas on the subject's dominant side. For dermatomal regions of the arm and forearm, mean values ranged from 30.7 mm to 45.4 mm. In the hand, the skin overlying the first dorsal interosseous muscle demonstrated discrimination values of 21.0 mm while that covering the volar surface of the tips of the thumb and long and little fingers showed values of 2.6 mm. Mean discrimination values for men and women in the test sample were not significantly different for any of the areas tested except the medial surface of the forearm where women showed a greater degree of sensitivity than men. The most striking observation was the large interindividual variation in two-point discrimination sensitivity. The existence of large interindividual variation within the normal population suggested that caution should be used when one is interpreting the results of two-point discrimination testing in select patient populations.

Adult

Ultrastructure and quantitative synaptology of the sacral parasympathetic nucleus.

This study examines the anatomical substrate for the spinal micturition reflex. Light microscopy of pyridine silver-stained sections revealed that the sacral parasympathetic nucleus (SPN) exists as a broken column or chain of cell clusters located along the intermediolateral portion of the dorsal horn in sacral segments S2-S4. Quantitative analysis of neuropil components in electron micrographs provides data for each type of bouton identified in this nucleus. On the somata of these neurons, boutons containing clear spherical vesicles (S type) comprise 70% of the bouton population. Terminals containing three or more dense core vesicles (GS boutons) account for 26% and boutons containing flattened vesicles (F boutons) comprise 4% of the population. F boutons are more common on large dendrites where they comprise 10% of the total bouton population. The actual population density of each bouton type is most evident when the number of boutons is expressed as boutons per 100 micron of membrane length (btn/100 micron). S type boutons are the most frequently encountered type. The population density of S boutons is the same on soma and dendrites at 6.66 btn/100 micron. F boutons are more numerous on large (greater than 2 micron) dendrites (1.28 btn/100 micron) than on small dendrites (0.63 btn/100 micron) or on somata (0.36 btn/100 micron). GS boutons occur more frequently on small dendrites (3.66 btn/100 micron) than on somata (2.29 btn/100 micron), large dendrites (2.88 btn/100 micron) or medium dendrites (2.27 btn/100 micron). These data suggest that the dense core vesicle-containing boutons are applied primarily to small (less than 1 micron) dendrites and that F boutons are associated mostly with large or proximal dendrites. These results provide a quantitative profile of the synaptic input to the sacral autonomic (parasympathetic) neurons which innervate the urinary bladder and demonstrate specific population differences on various postsynaptic structures in this nucleus.

Animals

An ultrastructural examination of dorsal root input to the sacral secondary visceral gray.

Dorsal root input to the sacral secondary visceral gray was examined in the adult cat using an orthograde degeneration technique. Five days after unilateral, intradural section of sacral dorsal roots electron-microscopic evidence of synaptic degeneration was seen throughout the nucleus ipsilateral to the side of the lesion. Degenerating sacral primary afferents in this nuclear region were associated mainly with S and GS type boutons. S type synapses showed two distinct degenerative responses. Some of the degenerating boutons were swollen with synaptic vesicles clustered tightly near the presynaptic membrane. Others appear shrunken with consequent packing of vesicles and mitochondria within the presynaptic terminal. Degenerating S terminals were found mainly on dendrites. S type synapses on nerve cell bodies appeared to be unaffected by dorsal root section. The degenerative response of sacral primary afferents associated with GS boutons was characterized by marked swelling of the presynaptic terminal and the presence of significant amounts of glycogen. Degenerating GS boutons were observed on both cell bodies and dendrites. These observations provide morphologic evidence of a direct synaptic link between dorsal root afferents and nerve cells in the sacral secondary visceral gray.

Animals