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Biomedical subjects

K S Lewis

Publications and source records attributed to K S Lewis.

At least 19 recordsLinked to original sources
PubMed1999

Chemical conditions inside occluded regions on corroding aircraft aluminum alloys.

Corrosion of aluminum alloy structures costs the US Air Force in the order of US$1 x 10(9) annually. Corrosion develops in areas of overlap such as aircraft lap-splice joints and under protective organic coatings. Capillary electrophoresis (CE) has been used to determine the local chemistries at these corrosion sites of solutions that were extracted using a microsampling system. Analysis of the local solution within lap-splice joints from aircraft has been performed in two ways: rehydration of corrosion products and direct microsampling. The solutions collected were analyzed with CE to quantitatively determine the species present during corrosion. The most common ions detected were Cl-, NO2-, NO3-, HCO3-, K+, Al3+, Ca2+, Na+ and Mg2+. Studies of the solution chemistry under local coating defects are required to understand coating failure and develop more durable coatings. A microsampling system and micro pH sensor were developed to extract solution from and measure pH in defects with diameters as small as 170 microns. Actively corroding defects contained high concentrations of Cl-, Al3+, Mg2+, Mn2+ and Cu2+ whereas only trace levels of Mg2+ were found in repassivated defects. The effects of these species on initiation and propagation of corrosion are discussed.

Aircraft↗
PubMed1997

Tramadol: a new centrally acting analgesic.

The pharmacology, pharmacokinetics, efficacy, adverse effects, and dosage and administration of tramadol are reviewed. Tramadol is a synthetic analogue of codeine that binds to mu opiate receptors and inhibits norepinephrine and serotonin reuptake. It is rapidly and extensively absorbed after oral doses and is metabolized in the liver. Analgesia begins within one hour and starts to peak in two hours. In patients with moderate postoperative pain, i.v. or i.m. tramadol is roughly equal in efficacy to meperidine or morphine; for severe acute pain, tramadol is less effective than morphine. Oral tramadol can also be effective after certain types of surgery. Tramadol and meperidine are equally effective in postoperative patient-controlled analgesia. In epidural administration for pain after abdominal surgery, tramadol is more effective than bupivacaine but less effective than morphine. In patients with ureteral calculi, both dipyrone and butylscopolamine are more effective than tramadol. For labor pain, i.m. tramadol works as well as meperidine and is less likely to cause neonatal respiratory depression. Oral tramadol is as effective as codeine for acute dental pain. In several types of severe or refractory cancer pain, tramadol is effective, but less so than morphine; for other types of chronic pain, such as low-back pain, oral tramadol works as well as acetaminophen-codeine. Common adverse effects of tramadol include dizziness, nausea, dry mouth, and sedation. The abuse potential seems low. The recommended oral dosage is 50-100 mg every four to six hours. Tramadol is an effective, if expensive, alternative to other analgesics in some clinical situations.

Analgesics, Opioid↗
PubMed1995

Characterization of human E4BP4, a phosphorylated bZIP factor.

In this report we described the isolation of transcription factor E4BP4 by lambda gt11 expression cloning using a probe containing the CRE/ATF-like sequence located between -2764 bp and -2753 bp in the upstream regulatory region for the human IL-1 beta gene. DNaseI protection, gel mobility shift analysis, and cotransfection studies were performed to investigate the binding and functional properties of E4BP4 using IL-1 beta promoter sequences. By DNaseI footprinting, a protection pattern was generated over the CRE/ATF-like site and the flanking sequences by bacterially produced E4BP4. Competition experiment by gel shift assay indicated that E4BP4 bound specifically to CRE/ATF-like site, not NF kappa B-like site. In cotransfection studies, E4BP4 repressed promoter activity and this repression was mediated through the CRE/ATF-like site. Mutational analysis of E4BP4 suggested that the DNA binding as well as repression activities required leucine heptad repeat domain. Analysis of E4BP4 produced in Escherichia coli and Sf9 cells infected with recombinant baculovirus indicated that baculovirus produced protein showed enhanced binding to the CRE/ATF-like site compared to the E. coli-produced protein. Analysis of posttranslational modifications indicated that E4BP4 produced in Sf9 cells was phosphorylated and this phosphorylation was important for the DNA binding activity of E4BP4.

Activating Transcription Factor 2↗
PubMed1994

Effect of analgesic treatment on the physiological consequences of acute pain.

Physiological responses to acute pain are described, and the effects of different analgesic techniques on these responses are discussed. The body's response to acute pain can cause adverse physiological effects. Pain can impede the return of normal pulmonary function, modify certain aspects of the stress response to injury, and alter hemodynamic values and cardiovascular function. It can produce immobility and contribute to thromboembolic complications. In addition, pain can slow a patient's recovery from surgery and contribute to increased morbidity. Fewer pulmonary complications occur when adequate analgesia is provided through the use of epidural narcotics and local anesthetics, particularly if the injury or surgery involves the lower part of the body. Continuous morphine infusions, intercostal nerve blocks, and transcutaneous electrical stimulation do not alter the frequency of pulmonary complications. The effectiveness of patient-controlled analgesia in reducing postoperative pulmonary complications is still not known. Epidural local anesthetic therapy inhibits the stress response, particularly in operations involving the lower abdomen or extremities; this technique is less effective during major abdominal procedures. Suppression of endocrine-metabolic changes following lower abdominal surgery requires neural block to the fourth thoracic segment. Epidural narcotics partially inhibit the stress response after lower abdominal or extremity surgery but not after upper abdominal or thoracic surgery. Local anesthetics applied to the surgical site, intercostal nerve blocks, and intrapleural and intraperitoneal administration also do not modify the stress response. Adequate analgesia through the use of local anesthetics and narcotics postoperatively generally results in improved cardiovascular function, decreased pulmonary morbidity and mortality, earlier ambulation, and decreased likelihood of deep vein thrombosis. Some data suggest that improved patient outcome occurs with adequate analgesia. Block of afferent and efferent neural pathways by local anesthetics seems to be the most effective analgesic modality in lessening the physiologic response to pain and injury.

Acute Disease↗
PubMed1994

Difficulties in diagnosing narcotic overdoses in hospitalized patients.

OBJECTIVE: To describe the clinical presentation of narcotic overdose in hospitalized patients and to differentiate this circumstance from other conditions often misdiagnosed as overdose. DESIGN: Case series. SETTING: Two acute-care teaching hospitals. PATIENTS: Forty-three hospitalized patients who received naloxone for a clinically suspected narcotic overdose. INTERVENTIONS: Two investigators independently evaluated each incident to determine whether the patient had a narcotic overdose. The patients were judged to have had an overdose if caregivers documented an immediate improvement in mental status, respiratory rate, or blood pressure after naloxone administration. MEASUREMENTS: The clinical presentation of a narcotic overdose in hospitalized patients was defined. Conditions misdiagnosed as an overdose were determined. MAIN RESULTS: Symptoms improved rapidly with the administration of naloxone in 28 incidents (65 percent) and were designated overdose. In 15 other instances there was no improvement in symptoms; these patients were designated nonoverdose. Only half of the overdose patients had a respiratory rate < 8 breaths/min immediately prior to naloxone administration. Only two of the overdose patients had the classic triad of symptoms (respiratory depression, coma, and pinpoint pupils). Other overdose patients had only one or two of the classic signs. The clinical presentation of narcotic overdoses in hospitalized patients did not include respiratory depression, hypotension, or coma in the majority of patients. All overdose patients showed a decrease in mental status. The majority of nonoverdose patients had pulmonary conditions that were misdiagnosed as a narcotic overdose. CONCLUSIONS: Narcotic overdoses in hospitalized patients seldom fit the classic description. The lack of respiratory depression does not mean the absence of a narcotic overdose. Patients who receive narcotics and develop a significant decrease in mental status should be evaluated for a possible overdose. Pulmonary, neurologic, cardiovascular, and electrolyte abnormalities often are misdiagnosed as a narcotic overdose in hospitalized patients.

Adolescent↗
PubMed1994

Identification of patient-controlled analgesia overdoses in hospitalized patients: a computerized method of monitoring adverse events.

OBJECTIVE: To describe and validate a computer-based quality assurance method that detects narcotic overdoses associated with patient-controlled analgesia (PCA) use. SETTING: Two acute care teaching hospitals. PATIENTS: 4669 patients who received PCA. INTERVENTIONS: The following patient lists were obtained during a two-year period from both hospital information systems: those who received PCA and (1) received naloxone, a narcotic antagonist, (2) were transferred to an intensive care unit, (3) had a cardiac or respiratory arrest, or (4) died. Possible overdoses were defined as patients who appeared on the PCA list and one of the other lists. Charts were reviewed if the patient's name appeared on the PCA and one of the other lists. Patients were judged to have experienced a narcotic overdose if there was an immediate improvement in blood pressure, respiratory rate, or mental status after the administration of naloxone. RESULTS: The search strategy identified 294 possible overdoses in 1499 patients who received PCA. Ten charts were unavailable for review. An actual overdose occurred in 11 patients. The accuracy of the new method was compared with that of the hospitals' present reporting methods. Eleven overdoses were identified by the computer search, but only 6 overdoses were identified in incident and adverse drug reaction reports. CONCLUSIONS: The systematic computer search identified almost twice as many adverse incidents than were reported by the traditional hospital methods.

Adverse Drug Reaction Reporting Systems↗
PubMed1993

Intrathecal baclofen for severe spasticity secondary to spinal cord injury.

OBJECTIVE: To evaluate the use of intrathecal baclofen for the treatment of muscle spasticity in patients with spinal cord injury. DATA SOURCES: A MEDLINE search was used to identify relevant and pertinent literature. Information was obtained from open-label clinical trials, abstracts, conference proceedings, and review articles. Index terms in the search included baclofen, spasticity, intrathecal drug infusion, spinal cord disease, and neurosurgery. DATA EXTRACTION: Studies were selected for review if they evaluated intrathecal baclofen in patients with spinal cord injury. Emphasis was placed on human studies published in the English language. Trials were reviewed by dosage regimen, therapeutic response, adverse effects, and complications. DATA SYNTHESIS: Thus far, intrathecal baclofen administration shows promise in the treatment of spasticity resulting from spinal cord trauma. Few complications and adverse effects have been reported. CONCLUSIONS: Muscle spasms and spasticity constitute a significant problem in spinal cord injuries, interfering with rehabilitation and leading to inconveniences and complications in these patients. Oral baclofen is the drug of choice for spasticity due to spinal cord trauma. It often is ineffective, however, because of the large dosages required to cross the blood-brain barrier and the subsequent appearance of central nervous system adverse effects. These adverse effects are not tolerated by many patients. Intrathecally administered baclofen has been approved by the Food and Drug Administration (FDA) for the treatment of spasticity in patients with spinal cord injury who are refractory to or cannot tolerate oral baclofen. It is intended for use only in implantable pumps approved by the FDA for the administration of baclofen into the intrathecal space. Intrathecal administration achieves high concentrations in the spinal cord with small dosages, thus reducing the incidence of central nervous system adverse effects. To date, approximately 350 patients with spinal cord injury have been treated with intrathecal baclofen. Reductions in spasticity have been demonstrated in both open-label and placebo-controlled trials. Patients also often make substantial gains in activities of daily living. Few adverse effects and complications have been reported. However, tolerance to the clinical effects of intrathecal baclofen has been reported. Further studies are needed to determine specific patient populations that may benefit most from intrathecal baclofen administration. Individual dosage ranges and follow-up care also need to be defined more completely. In addition, the question of whether tolerance detracts from long-term clinical benefits with intrathecal baclofen needs to be addressed.

Baclofen↗
PubMed1991

Randomized trial comparing continuous subcutaneous insulin infusion and conventional insulin therapy in type II diabetic patients poorly controlled with sulfonylureas.

OBJECTIVE: To compare the effects of continuous subcutaneous insulin infusion (CSII) and conventional insulin therapy (CIT) in patients with poorly controlled sulfonylurea-treated diabetes mellitus. RESEARCH DESIGN AND METHODS: Twenty-five patients aged 40-65 yr and poorly controlled with sulfonylureas and without severe diabetic complications comprised the study group. Five patients left the study (3 achieved satisfactory glycemic control without insulin, 1 defaulted, 1 developed ketonuria). Ten patients were treated with CSII and 10 with CIT. Outpatient treatment consisted of CIT (twice-daily injections of regular and NPH insulin) or CSII (basal infusion and prandial boluses of regular insulin). RESULTS: Glycosylated hemoglobin improved with both methods of insulin delivery (P less than 0.01), but 8 of 10 CSII-treated patients achieved satisfactory glycemic control (HbA1 less than 50 mmol hydroxymethylfurfural/mol Hb), whereas only 3 of 10 CIT-treated patients achieved this (P less than 0.05). Weight gain, insulin dosage, and prevalence of hypoglycemia were similar in the two groups. Retinal deterioration occurred in one CSII-treated patient and three CIT-treated patients, but there were no episodes of infusion site infection or metabolic decompensation. Patients' satisfaction with treatment improved during insulin therapy (P less than 0.02), and significant changes in beliefs about diabetes and its treatment were observed in CSII-treated patients (P less than 0.05). CONCLUSIONS: Glycemic control improved with both methods of insulin treated patients achieved satisfactory glycemic control (HbA1 less than 50 mmol hydroxymethylfurfural/mol Hb), whereas only 3 of 10 CIT-treated patients achieved this CSII. Patients' satisfaction with treatment improved during insulin therapy.

Adult↗
PubMed1991

Medical record review for clinical pertinence.

This clinical pertinence review process described was in effect for seven months, after which the author terminated affiliation with the hospital. Despite resistance by many physicians, this monthly review process focused the medical staff's attention on good documentation practices. To the author's knowledge, the plan is still in use.

Documentation↗
PubMed1990

Health belief scales developed specifically for people with tablet-treated type 2 diabetes.

The design and development of scales to measure diabetes-specific health beliefs of patients treated with oral hypoglycaemic agents and diet are described. The scales, which were developed from the responses of 187 tablet-treated patients, measure perceived Benefits of, and Barriers to Treatment, and perceived Severity of, and Vulnerability to Complications of diabetes and other disorders unrelated to diabetes. Cronbach's alpha indicated that each scale was internally reliable (alpha = 0.67 to 0.89) and construct validity was indicated by expected correlations between the scales and other variables including measures of blood glucose control, body weight, and psychological well-being. Thus, patients who were overweight and/or had higher glycosylated haemoglobin (HbA1) levels perceived their treatment to be less 'Cost-effective' (Benefits less Barriers), rated Complications as being more severe, and reported greater Vulnerability for themselves and the 'average person' with diabetes to these Complications (p less than 0.05 to p less than 0.01). Furthermore, respondents with higher Depression and Anxiety scores and lower Positive Well-being and Treatment Satisfaction scores reported greater Vulnerability to Complications for themselves and the 'average person', and also felt that their treatment was less 'Cost-effective' (p less than 0.01 to p less than 0.001). The measures are likely to be particularly useful in studies which assess the efficacy of interventions in modifying health beliefs with a view to achieving desired behaviours. They may also be useful as an instrument of audit if indicators about the suitability of possible interventions are sought.

Adult↗
PubMed1990

Measures of psychological well-being and treatment satisfaction developed from the responses of people with tablet-treated diabetes.

Psychological outcome measures of Well-being and Treatment Satisfaction have been designed and developed for people with tablet-treated Type 2 diabetes. The Well-being scale includes three six-item sub-scales to measure Depression, Anxiety, and Positive Well-being. A prime consideration when selecting items for the psychological well-being measures was to minimize the confounding of diabetic symptomatology with the somatic symptoms of depression and anxiety. Cronbach's alpha indicated that each of the Well-being sub-scales and the Treatment Satisfaction scale was internally reliable (alphas ranged from 0.70 to 0.88) and evidence for construct validity was provided by predicted associations with other variables collected at the time of the study. For example, lower Well-being scores were associated with being overweight (Depression: p less than 0.05; Anxiety: p less than 0.001) while greater Satisfaction with Treatment was associated with lower HbA1 levels (p less than 0.001) and lower percent ideal body weight (p less than 0.01). These scales should prove particularly useful where measures of quality of life are required to complement metabolic variables when evaluating new treatments, education programmes, and other interventions, or in the routine auditing of established methods of treatment.

Adult↗
PubMed1988

A measure of treatment satisfaction designed specifically for people with insulin-dependent diabetes.

The psychometric properties of a diabetes-specific treatment satisfaction scale were examined with responses from 128 adults with insulin-dependent diabetes who had used one of three treatment options for a period of 12 months. The reliability of the seven-item measured was found to be satisfactory (Cronbach's Alpha = 0.76) and factor analyses indicated three useful sub-scales (Perceived General Management; Perceived Compatibility with Lifestyle; Perceived Frequency of Hypo/hyperglycaemia). Use of the treatment satisfaction measure in a feasibility study of continuous subcutaneous insulin infusion (CSII) demonstrated the measure's ability to distinguish between three treatment groups (CSII, intensified conventional therapy and conventional therapy). People choosing to use CSII reported significantly greater improvements in satisfaction than those choosing either from of conventional therapy (F = 36.6; df 2, 125; p less than 0.001). If used in conjunction with measures of blood glucose control, the Treatment Satisfaction measure offers the opportunity for a more holistic appraisal of outcomes in studies evaluating and comparing treatments for insulin-dependent diabetes.

Adolescent↗