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Biomedical subjects

A H White

Publications and source records attributed to A H White.

At least 37 records · Page 2Linked to original sources
PubMed1995

Cyanogenic and non-cyanogenic glycosides from Manihot esculenta.

In addition to lotaustralin and linamarin, a novel cyanogenic glycoside, 2-((6-O-(beta-D-apiofuranosyl)-beta-D-glucopyranosyl)oxy)-2-met hylbutanenitrile , two novel non-cyanogenic glycosides, (2S)-((6-O-(beta-D-apiofuranosyl)-beta-D- glucopyranosyl)oxy)butane and 2-((6-O-(beta-D-apiofuranosyl)-beta-D-glucopyranosyl)oxy)propane, and a simple non-cyanogenic glycoside, ethyl beta-D-glucopyranoside, were isolated from an ethanolic extract of the fresh root cortex of Manihot esculenta. From a methanolic extract of the fresh leaves of this species lotaustralin and linamarin, and two flavonoid glycosides, kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside were isolated.

Carbohydrate Sequence↗
PubMed1994

Magnetic resonance imaging of a thoracic intraspinal synovial cyst.

A 50-year-old woman presented with mid-thoracic back pain that radiated to the left rib cage in a radicular manner. Magnetic resonance imaging revealed an extradural mass compressing the left T9 nerve root. The mass was adjacent to a degenerated T9-10 facet joint with an enhancing low signal intensity rim. Recognition of the characteristic imaging findings of an intraspinal synovial cyst resulted in the correct preoperative diagnosis despite the unusual location of this lesion at T9-10.

Female↗
PubMed1992

Response to steroid and duration of radicular pain as predictors of surgical outcome.

Prolonged structural compromise of spinal nerve roots can lead to chronic changes that surgical decompression might not be able to reverse. In this study, it was hypothesized that if there were a reversible structural pain component, a steroid injected into the patient's symptomatic nerve root should provide temporary pain relief and that these patients should have a favorable surgical outcome. It also was hypothesized that duration of radicular symptoms would correlate inversely with surgical outcome. For postoperative relief of radicular pain, the results showed that patients with pain lasting less than 1 year had a positive surgical result (89%), regardless of response to steroid. Patients with pain lasting more than 1 year and who have had a positive response to steroid injected into the symptomatic nerve root (roots) had a positive surgical outcome of 85%. Patients who did not respond to the steroid and had pain for more than 1 year (95%) generally had a poor surgical outcome. Although the poor outcome in the last group might be explained in some cases by an inadequate structural correction, inadequate stabilization, or functional reasons, the majority of these failures represented irreversible changes in the neural structures.

Betamethasone↗
PubMed1990

High levels of inflammatory phospholipase A2 activity in lumbar disc herniations.

Inflammation of neural elements is frequently mentioned clinically in association with lumbar radiculopathy. Mechanical embarrassment of neural elements by definable structural abnormalities is inadequate as a sole explanation of nerve injury in this condition. The purpose of this study was to demonstrate whether an enzymatic marker for inflammation (phospholipase A2) could be identified in human disc samples removed at surgery for radiculopathy due to lumbar disc disease. Samples were assayed for phospholipase A2 activity. The level of activity in the disc samples was compared with values obtained from other human tissues using the same assay. Specific activity (percent hydrolysis radiolabelled substrate) ranged from 238 to 1,014.5 nmol/min/mg. Mean activity for the human disc material was 568.7 nmol/min/mg, compared with 0.006 nmol/min/mg for human PMN, and 12.1 nmol/min/mg for inflammatory human synovial effusion. The pH and cation-related activity were identical to those demonstrated for phospholipase A2 inflammatory conditions. Human lumbar disc phospholipase A2 activity is from 20- to 100,000-fold more active than any other phospholipase A2 that has been described. As the enzyme responsible for the liberation of arachidonic acid from cell membranes, phospholipase A2 is the rate-limiting step in the production of prostaglandins and leukotrienes. These data establish biochemical evidence of inflammation at the site of lumbar disc herniations.

Biomarkers↗
PubMed1989

Absorption, distribution, metabolism, and excretion of furazolidone. A review of the literature.

Systematic determination of profiles of absorption, distribution, metabolism, and excretion of drugs is standard in the pharmaceutical industry today, and powerful, precise, and specific analytical methods are available to carry out such studies. In the case of furazolidone, developed in the late 1940s, the data were obtained with less precise analytical procedures. This gave rise to the misconception that furazolidone is poorly absorbed and inactivated in the intestine. Newer techniques, such as chromatography and 14C studies, have helped to establish that the drug is indeed well absorbed. Levels of radiolabeled analyte measured in urine indicate that more than 65% of an oral dose is recovered in each animal species tested. Chromatographic methods indicate that little or no intact drug is recovered.

Diarrhea↗
PubMed1988

Painful lumbar end-plate disruptions: a significant discographic finding.

Of the 692 discs injected during lumbar discograms, end-plate disruptions with leakage of contrast material into the vertebral bodies were noted in 14 discs. Although gentle pressure was applied during the injections, severe fully concordant pain was reproduced in four (28.3%) discs, moderately severe and fully concordant pain in nine (64.3%) discs, and mild discordant pain in one (7.4%) disc. This is compared to 11.2% of the remaining 678 discs without end-plate disruption that reproduced severe concordant pain, 31.1% with moderately severe concordant pain, 17.1% with mild pain, and 40.6% without any pain reproduction. The difference between pain frequency in discs with end-plate disruption and those without is statistically significant (P less than .001). This suggests that end-plate disruptions may be related to painful segments.

Adolescent↗
PubMed1987

Lumbar laminectomy for herniated disc: a prospective controlled comparison with internal fixation fusion.

This is a controlled prospective study on a matched set of patients with herniated lumbar discs. Both groups received the same bilateral lumbar laminectomy and disc excision by the same surgeon. One group had the addition of an intertransverse fusion with internal fixation. Both groups were studied by an independent examiner at an average of 3 years postoperatively for success rate as determined by activity level, medication, subjective and objective evaluation. Both groups had similar age, sex, and occupational characteristics. No patient had prior surgical treatment or chemonucleolysis. Patients with associated lumbar spine problems such as stenosis, instability, or spondylolisthesis were excluded. Each patient had a positive clinical picture for a herniated lumbar disc, as well as a positive myelogram, venogram or computerized tomographic scan. Most had positive electromyograms. All patients received at least 3 months of conservative care. The 38 patients with fusion had a significantly longer mean time to return to work after surgery versus the 31 patients without fusion. Although the general success rate of both groups was 87%, the best results were in the nonfusion group. A total of 29% of nonfusions had excellent results whereas only 11% of the fusion group had excellent results. The conclusion is that fusions are not necessary and give less excellent results in simple laminectomy cases for herniated lumbar disc.

Adult↗
PubMed1986

Lumbosacral fusions with Harrington rods and intersegmental wiring.

Harrington rods are a valuable adjunct for fusion of the lumbosacral spine. Major limits of distractions are achieved with these rods. Greater amounts of decompression are possible. Decompression, alignment, and stability are maintained. Intersegmental wiring increases security and eliminates the problem of hook and rod displacement and loss of lumbar lordosis. A variety of methods are available for sacral fixation to avoid neurologic complications from the distal hooks. Three- and four-level Harrington rod distraction lumbosacral fusions have proven to be successful in returning severely-disabled spinal stenotic, obese, and osteoporotic patients to normal activities.

Bone Wires↗
PubMed1985

Low back pain.

Optimization of the surgical results on low back pain requires changing the factors that led to the patient's surgical disorder. The factors are poor posture, improper body mechanics, weakness, abusive activities, and general lack of understanding of back health care. Education and exercise will change all of these factors and help prevent the epidemic of failed multioperated patients with back problems. On surgery one should consider the natural history of lumbar spinal degeneration, anticipate failure, and do it right the first time.

Back Pain↗
PubMed1985

A model for conservative care of low back pain: back school, epidural blocks, mobilization.

Conservative care for low back pain can be an enjoyable and successful experience for the physician. It requires a bit more organization and assistance than other routine forms of orthopaedic practice. It begins with a systematic collection of historical and physical information. The most appropriate conservative treatment is selected specifically for the patient's diagnosis. The patient's participation is required in the conservative treatment, and he must be willing to take responsibility for his condition. Education and training are the mainstay of conservative treatment with the addition of injections, braces, mobilization, medication, or rest as temporary adjuncts.

Anti-Inflammatory Agents↗
PubMedDate not supplied

Role socialization of graduating student nurses: impact of a nursing practicum on professional role conception.

This study examined graduating student nurse role conception changes that occurred during a concentrated clinical preceptorial. A Nursing Role Conceptions Questionnaire was administered to nursing students before (n = 44) and immediately after (n = 41) a 4-week Nursing Practicum; to the students' staff nurse clinical teaching associates (n = 34); and to nursing program faculty (n = 18). Respondent perceptions of ideal nursing behaviors and actual nursing behaviors within three major nursing roles (professional, service, and bureaucratic) were identified and differences between ideal and actual scores (role discrepancy) were calculated. Findings showed that student role orientation in selected areas changed from a faculty role orientation to a staff nurse role orientation over the 4-week period. The Practicum seemed to effectively facilitate role socialization of graduating student nurses into the work setting, easing the necessary transition from education to practice.

Education, Nursing↗
PubMedDate not supplied

Biologically active metabolites from Xenorhabdus spp., Part 1. Dithiolopyrrolone derivatives with antibiotic activity.

Five related antibiotic compounds, named xenorhabdins, were isolated from cultures of Xenorhabdus spp., bacteria symbiotically associated with insect-pathogenic nematodes. Their chemical structures were elucidated by X-ray crystallography, nmr, and mass spectral analyses to be N-acyl derivatives of either 6-amino-4,5-dihydro-5-oxo-1,2-dithiolo [4,3-b] pyrrole (compounds 1-3) or 6-amino-4,5-dihydro-4-methyl-5-oxo-1,2-dithiolo[4,3-b] pyrrole (compounds 4 and 5). They are previously unreported members of the pyrrothine family of antibiotics. Antimicrobial and insectidical activities were found. These metabolites are specific to phase one Xenorhabdus.

Anti-Bacterial Agents↗
PubMedDate not supplied

From authorship to contributorship. Promoting integrity in research publication.

Shared authorship in nursing research presents practical and ethical dilemmas and does not effectively capture individual research participation and accountability. This study, which defined author contributions and practices in multiauthored nursing research, contributed to a better understanding of contemporary author participation and the inherent challenges faced by nurse scholars in determining authorship credit. A method of "contributorship" is proposed which would delineate individual contributions to the research project while maintaining professional integrity, scientific accountability, and scholarly recognition.

Attitude of Health Personnel↗
PubMedDate not supplied

Epidural injections for the diagnosis and treatment of low-back pain.

Three hundred four consecutive patients with low-back pain were given epidural anesthetic and steroid injections. A prospective study demonstrated that selected patients had 87% short-term success and 34% relief of pain for as long as 6 months. No patient was cured by these injections. Needle placement during epidural injections was incorrect 25% of the time in experienced hands.

Adult↗
PubMedDate not supplied

Knodt rod distraction lumbar fusion.

Ninety-nine cases of Knodt rod fusions have been followed for an average of 18 months postoperatively. These patients were all severely incapacitated with pain for an average of 5.3 years prior to surgery. They all had a thorough preoperative work-up including myelogram, EMG and extensive conservative care. The procedure performed was an extensive bilateral laminectomy of the L5 vertebra with foramenotomy and a posterior lateral intertransverse fusion with the use of Knodt rods between the L4-5 and S1 levels. There was an overall average improvement after surgery in 70.35% of the cases. When the consideration of psychological problems and industrial cases were eliminated, the overall improvement was 80.38%. There were no major complications except that in five patients the Knodt rods were removed from between one week and one year postoperatively. Knodt rod fusions have results reported in the literature of frequent complications and very poor success rates. They can be a very good adjunct to the spine surgeon's armamentarium. In patients with long-range back pain who plan to return to heavy labor, the Knodt rods can give a surprisingly high rate of success.

Adult↗