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Biomedical subjects

W C Parris

Publications and source records attributed to W C Parris.

At least 37 records · Page 2Linked to original sources

In vitro effects of fluoride and bromide on pseudocholinesterase and acetylcholinesterase activities.

The in vitro effects of two metabolites of inhalational anaesthetics, fluoride and bromide, on pseudocholinesterase (PCHE) and acetylcholinesterase (ACHE) activities in the blood samples of seven healthy patients were studied. The PCHE and ACHE activities were determined by kinetic spectrophotometric methods. Fluoride at the levels achieved with clinical concentrations of enflurane and sevoflurane (25-75 microM.L-1) inhibited PCHE activity by 28-65 per cent (P less than 0.01) and ACHE activity by less than five per cent (P greater than 0.05). Bromide at the levels achieved with clinical concentrations of inhalational anaesthetics had no significant effect on either PCHE or ACHE activity. We recommend caution when succinylcholine and/or ester type local anaesthetics are used in the immediate postoperative period following enflurane or sevoflurane anaesthesia. We also recommend that blood drawing for PCHE activity be delayed at least until 24 hr following enflurane or sevoflurane anaesthesia.

Acetylcholinesterase↗

Effects of significant weight gain on chronic pain patients.

This study examined the effect of significant weight gain on physical, demographic, behavioral, and psychosocial factors in a representative sample of chronic pain patients. One hundred fifty-five chronic pain patients who reported gaining more than 15 pounds since the onset of their pain were compared with 341 pain patients who stated that their weight had remained the same since the onset of their pain. All patients were given a medical examination and each patient completed a comprehensive pain questionnaire and an SCL-90. Results showed that a significant relationship exists between weight gain and decreased physical activity, increased emotional distress, and accident liability. This study suggests that the inclusion of weight management training in multidisciplinary pain centers may play an important part in the rehabilitation of chronic pain patients.

Adolescent↗

Immunoreactive substance P is decreased in saliva of patients with chronic back pain syndromes.

Substance P, a neuropeptide associated with pain perception, is widely distributed in the central nervous system and is decreased in the cerebrospinal fluid of chronic pain patients as compared with that of healthy human volunteers. In this study, we have demonstrated the presence of immunoreactive substance P in saliva and further, that both saliva and plasma levels of immunoreactive substance P are lower in patients with chronic low back pain than in healthy human volunteers. To our knowledge, this is the first time that substance P has been identified in human saliva. These findings, together with the noninvasive nature of saliva collection, suggest that substance P in saliva may be useful as an alternative neurochemical correlate of chronic low back pain when collection of cerebrospinal fluid and plasma samples for substance P analysis is unacceptable or inappropriate.

Back Pain↗

Intrapleural analgesia for post-thoracotomy pain and blood levels of bupivacaine following intrapleural injection.

An epidural type catheter was placed in the pleural space under direct vision before the closure of the chest in 24 patients who underwent thoracotomy for various types of lung or aortic surgery. All patients received intrapleural injections of 20 ml of 0.5 per cent bupivacaine with or without epinephrine as initial pain therapy. Patients also received subsequent doses of a similar volume of 0.375 per cent bupivacaine with epinephrine 1:200,000 up to four times a day for a maximum duration of seven days. Good pain relief was achieved in patients who underwent lateral and posterior thoracotomies. No pain relief was achieved in patients who underwent anterior thoracotomy or in patients in whom there was excessive bleeding in the pleural space. Bupivacaine blood concentrations were measured in 11 patients following the initial dose of 20 ml of 0.5 per cent bupivacaine (with epinephrine 1:200,000 in five of the 11 patients). The mean peak plasma concentration of bupivacaine when used with epinephrine was 0.32 +/- 0.02 microgram.ml-1. The mean peak plasma concentrations of bupivacaine when used without epinephrine was 1.28 +/- 0.48 microgram.ml-1. Our present data show that intrapleural analgesia is useful in the management of postoperative pain in patients who undergo thoracotomy. Our data also show that there is a significant decrease in peak plasma concentrations of bupivacaine when epinephrine is added to the solution (P less than 0.05).

Adult↗

Pseudocholinesterase activity in human cerebrospinal fluid.

Pseudocholinesterase (PCHE) activity and dibucaine numbers (DN) in the cerebrospinal fluid (CSF) and plasma of 10 ASA physical status 1 and 2 patients were measured using a kinetic method. CSF had a mean PCHE activity of 0.018 +/- 0.013 unit/ml with a DN of 59 +/- 4. Whereas, PCHE activity and DN in the plasma were 0.960 +/- 0.12 units/ml and 84 +/- 3, respectively. We also measured PCHE activity and DN in the CSF and plasma of 4 patients in whom there was a recent history of intraventricular bleeding. These patients had a CSF PCHE activity of 0.340 +/- 0.07 units/ml (DN = 78 +/- 3) and a plasma PCHE activity of 0.950 +/- 0.10 units/ml (DN = 82 +/- 2). Our data show that there is a low activity of PCHE in CSF, 1/20-1/100th that of plasma. Our data also show that PCHE activity increased to 1/4 to 1/2 that of plasma in CSF of patients with bleeding into CSF.

Adult↗

Empirically derived Symptom Checklist 90 subgroups of chronic pain patients: a cluster analysis.

Four hundred fifty-three chronic pain patients completed a Symptom Checklist 90 (SCL-90) and a comprehensive pain evaluation questionnaire. All patients were evaluated by a physician and rated on degree of pain pathology and pain behavior. The SCL-90 data were analyzed using two clustering procedures and replicated over two similar samples. Three distinct profiles emerged and represented high, medium, and low scores on the SCL-90. No differences were found between subgroups on demographic characteristics, compensation status, pain duration, or pain ratings. Patients in the high-profile subgroup showed the most emotional distress, reported that their pain interfered the most with all activities, and were most often judged to have high pain behavior. Little evidence was found to support a "denial" profile, as previously predicted. Further support was found for using the SCL-90 in assessing chronic pain patients.

Activities of Daily Living↗

Effect of sevoflurane on P50 and on measurement of oxygen tension.

Fresh samples of heparinized human blood from 10 healthy nonsmoking volunteers were used to study the effect of the inhaled anesthetic sevoflurane on the oxygen half-saturation pressure of hemoglobin (P50) and on polarographic measurements of oxygen tension at low values. Control samples had a baseline P50 of 26.9 +/- 0.2 mm Hg. When the blood samples were exposed to 1.75% (1 minimum alveolar concentration, MAC), 2.75%, and 3.5% (2 MAC) of sevoflurane, the P50 values were 27.0 +/- 0.5 mm Hg, 27.1 +/- 0.4 mm Hg, and 26.9 +/- 0.5 mm Hg, respectively. Our present data show that 1 to 2 MAC sevoflurane has no significant effect on P50 (P greater than 0.05). Our data also show that sevoflurane did not interfere with polarographic measurements of oxygen tension (P greater than 0.05). Other inhaled agents--halothane, enflurane, and isoflurane--do interfere with these measurements, and we cannot explain the difference.

Anesthesia, Inhalation↗

Pre-treatment with somatostatin in the anaesthetic management of a patient with carcinoid syndrome.

Carcinoid syndrome produces flushing, bronchoconstriction and gastrointestinal hypermotility secondary to serotonin, histamine, bradykinin and prostaglandin release. A variety of drugs, foods and anaesthetic agents may provoke this syndrome. Under anaesthesia, the flushing produced may be associated with acute hypotension and cardiovascular collapse; this phenomenon is called a carcinoid crisis. Recently, somatostatin analogue has been used successfully to treat intraoperative carcinoid crisis. In this report, we present a 66-year-old lady with carcinoid syndrome who was pre-treated with 50 micrograms somatostatin analogue IV and IM prior to surgical manipulation. The anaesthetic course was relatively uneventful and the patient did well postoperatively.

Aged↗

The inhibitory effect of metoclopramide on plasma cholinesterase activity.

The in vitro effect of metoclopramide on plasma cholinesterase (PCHE) activity was studied to investigate a mechanism for metoclopramide-induced prolongation of succinylcholine action. The mean PCHE of the control samples was 0.86 +/- 0.02 unit.ml-1. PCHE activity in the presence of metoclopramide, at concentrations of 0.05, 0.10, 0.50, 1.0, 2.5 and 5.0 micrograms.ml-1, was reduced to 0.78 +/- 0.02, 0.69 +/- 0.04, 0.50 +/- 0.03, 0.39 +/- 0.02, 0.24 +/- 0.01 and 0.15 +/- 0.01 unit.ml-1, respectively. Our data demonstrated that PCHE activity was significantly depressed by metoclopramide at all concentrations studied (p less than 0.001). Our data also show that the concentration of metoclopramide required to inhibit 50 per cent of PCHE activity (I50) was 0.8 micrograms.ml-1 (2.4 x 10(-6) M). We recommend caution when succinylcholine and or ester type local anaesthetics are administered to patients who are also receiving metoclopramide, especially in high doses.

Adult↗

Effects of time-limited vs unlimited compensation on pain behavior and treatment outcome in low back pain patients.

A common theme in the pain literature is that worker's compensation reinforces pain behavior and adversely influences treatment outcome of chronic pain patients. This study compared 110 chronic low back pain males divided into three groups: 44 receiving no compensation, 27 receiving time-limited worker's compensation, and 39 receiving unlimited social security disability benefits. All patients participated in a multimodal treatment program (e.g. nerve blocks, transcutaneous electrical nerve stimulation, relaxation training, biofeedback). Physician ratings of pain behavior and self-report measures of pain characteristics, activity level, and medication intake were gathered pretreatment; self-report measures were collected again approximately one year following treatment. The results showed disability patients to have a higher percentage of physician rated symptom dramatization and pain behavior and a greater usage of medication compared with the non-compensation and time-limited worker's compensation patients. At follow-up, no between group differences were found on measures of pain intensity, medication usage and activity. In general, however, more worker's compensation and non-compensation patients who were initially not working had returned to work at the time of follow-up compared with the disability patients. These results suggest that time-limited compensation may not affect treatment outcome or interfere with return-to-work chances while unlimited compensation may adversely influence the probability that patients will return to work. These findings support the notion that worker's compensation patients receiving time-limited financial benefits do not necessarily represent a 'problem' subgroup of chronic pain patients.

Adult↗

The influence of problems with concentration and memory on emotional distress and daily activities in chronic pain patients.

This study examined concentration and memory problems in chronic pain patients as they related to emotional distress and interference with daily activity. Three hundred and sixty-three chronic pain patients were divided into two groups based on how much they expressed difficulty in concentrating and remembering things. Each patient was given a physical examination and completed a pain evaluation questionnaire and an SCL-90. Physician ratings of the patients' depression and anxiety were also obtained. The results showed that problems in concentration and memory were related to emotional distress, poor family support, and interference with daily activities. It is suggested that techniques to improve concentration and memory should be incorporated as part of a multidisciplinary pain program.

Activities of Daily Living↗

Treatment outcome in low back pain patients: do compensation benefits make a difference?

Some evidence suggests that chronic pain patients who receive worker's compensation benefits have a tendency to exaggerate their symptoms and not benefit from treatment. This study compared 110 male chronic low back pain patients receiving either no compensation, time-limited compensation, or unlimited compensation on pretreatment and follow-up variables. The patients who received unlimited compensation tended to have a higher percentage of physician-rated symptom dramatization, to have more pain behavior, and to use more medication than the no-compensation and time-limited compensation patients. At follow-up, fewer patients with unlimited compensation had returned to work as compared with the other groups. These results suggest that time-limited compensation may not affect treatment outcome or interfere with return to work, while unlimited compensation may adversely influence overall treatment outcome and the probability that patients will return to work.

Back Pain↗

Use of epidural blood patch in treating chronic headache: report of six cases.

Chronic headaches are difficult problems to manage effectively. A select group of six patients with headache symptoms (throbbing headaches, located in the frontal or occipital areas; aggravated by ambulation and relieved by recumbency) resembling post-dural puncture headache received epidural blood patches using autologous blood for their chronic headaches. Five of the six patients obtained effective and sustained pain relief. All of the patients had received placebo injections with normal saline in the paraspinous muscles, without effect. The mechanism of action of the blood patch in these patients is unclear. It is possible that the headache may have been caused by a low pressure cerebrospinal fluid state, due to an unknown anatomical or physiological defect of the ventriculo-spinal system. Further studies are needed to evaluate this treatment modality.

Adult↗