Search PubMed⌕ Search

Biomedical subjects

S Allen

Publications and source records attributed to S Allen.

At least 253 records · Page 14Linked to original sources
PubMed1986

Influence of the 30 degrees laterally inclined position and the 'super-soft' 3-piece mattress on skin oxygen tension on areas of maximum pressure--implications for pressure sore prevention.

The measurement of the transcutaneous PO2 (tc PO2) demonstrates that localized pressure on skin sites under bony prominences (e.g., the sacral and trochanteric areas) decreases the tc PO2 at these skin positions to zero when subjects are lying motionless on a normal hospital mattress. This explains the high risk of pressure sore formation in elderly patients, who have a greatly reduced frequency of involuntary movements. Therefore, the first principle of pressure sore prevention is the elimination of localized pressure on both the trochanteric and sacral skin areas simultaneously. This can be achieved by bedding elderly patients who are at risk on a 'super-soft' mattress and by turning them regularly to the 30 degrees laterally inclined position. With healthy adults, placed in this position, both the skin areas over the trochanteric and sacral bony prominences remain almost free from pressure and thus normally oxygenated. In addition, the tc PO2 measurement allows an immediate assessment of the efficacy of a procedure for sore prevention.

Beds↗
PubMed1986

Eosinophilic vasculitis leading to amaurosis fugax in a patient with acquired immunodeficiency syndrome.

A 49-year-old bisexual man with generalized lymphadenopathy and antihuman T lymphocyte virus, type III, (HTLV-III) antibodies presented with recurrent, unilateral amaurosis fugax. A temporal artery biopsy specimen showed eosinophilic vasculitis. The patient then developed acquired immunodeficiency syndrome with Kaposi's sarcoma. We describe this patient because of the unusual association of large vessel vasculitis and acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1985

A comparison of Hexabrix and Renografin-60 in knee arthrography.

Forty patients were randomized in a double-blind study to compare the safety and diagnostic quality of Hexabrix vs. Renografin-60 without epinephrine in knee arthrography. Hexabrix is a monoacidic dimer of meglumine and sodium salts of ioxaglic acid with a lower osmolality than conventional contrast agents of similar concentration (32% iodine). Initial films were of equally high diagnostic quality for both groups, but delayed films at 20 and 30 min significantly favored Hexabrix for diagnostic quality. Hexabrix proved to be a safe and effective contrast agent for knee arthrography.

Adolescent↗
PubMed1985

Nuclear peptides from calf liver: large scale isolation and fractionation; control of gene expression in cell-free systems, and inhibition of growth of cells in culture.

DNA and nuclear RNA fractions contain small peptides (mol. wt. 600 - 1500) attached noncovalently. A large scale isolation procedure was developed for the extraction of such peptides directly from the lysed nuclei. Further purification and fractionation was performed with the chromatography on Sephadex, silica gel and h.p.l.c. C18 reverse phase columns. H.p.l.c. fractionation yielded eleven peaks. The peptides are rich in serine, glycine, alanine and acidic amino acids. They do not contain sulphur-containing amino acids. Only occasionally tyrosine, phenylalanine, histidine, arginine, and very moderate amount of lysine are found. These peptides are active in inhibiting gene expression in cell-free systems and incorporation of labeled thymidine in L 1210 murine leukemic cell culture. Thorough and exhaustive analysis demonstrated that the isolated peptides are not degradative products of histone or nonhistone chromosomal proteins.

Amino Acids↗
PubMed1985

Pharmacokinetics of low-dose 1-beta-D-arabinofuranosylcytosine given by continuous intravenous infusion over twenty-one days.

The pharmacokinetic parameters of low dose 1-beta-D-arabinofuranosylcytosine (ara-C) infusions were studied in 11 patients, 6 males and 5 females, with a mean age of 68.5 +/- 13.8 (SD) years. The drug was infused to 4 patients with pre-leukemia (refractory anemia with excess blasts), 5 patients with acute myelogenous leukemia, and 2 patients with secondary leukemia due to chemotherapy, at a dosage of 20 mg/m2/day over 21 days. The patients' blood and urine were analyzed for ara-C content by radioimmunoassay. Mean steady state plasma levels of 7.7 +/- 4.7 ng/ml (31.7 +/- 19.3 nM) (n = 189) and a range 0.6 (2.5 nM) (lower limit of assay) to 29.7 ng/ml (122.1 nM), with significant inter- and intra-patient variations, were reached within about 2.7 h. The plasma levels of ara-C decreased rapidly, with a t1/2 alpha of about 12 min following discontinuation of the infusion, followed by a very slow t 1/2 beta of about 19 h. Other parameters (mean values of 10 or 11 patients) were: area under the curve, 182.1 +/- 64.8 ng X day/ml; total body clearance, 188.7 +/- 54.8 liters/h; renal clearance, 3.1 +/- 1.4 liters/h; volume of distribution at steady state, 53,913 +/- 17,626 liters; and recovery of ara-C in urine, 1.43 +/- 0.69% (n = 226) of daily administered ara-C. A linear relationship was observed with administered dose when the mean plasma levels of our study were compared with the ones reported for conventional ara-C infusions. Plasma clearance was comparable to that observed in conventional dose, when the observed values were extrapolated to the dose administered in this study.

Aged↗
PubMed1985

Rubella susceptibility in young adults.

Despite widespread availability of rubella vaccine, a substantial group of young women remain at risk for delivery of infants with congenital rubella syndrome. In this study of 224 women students of childbearing age seen at a university gynecological clinic, 10.3 percent were shown serologically to have nonimmune rubella status. Of this group only five women returned for free immunization. Compliance and motivation appeared lacking. Patient history of infection or immunization was found to be unreliable; 59 percent of the sample population were uncertain of their immune status, and 32 percent showed poor understanding of rubella. Serological testing appears to be the only reliable test for detecting immune status.

Adult↗
PubMed1984

A rapid and safe method of estimating nanomole quantities of P, K+, Na+, Ca2+, and Mg2+ in plant material by perchloric acid digestion.

A method for the determination of nanomole amounts of P and major cations in samples of dried plant tissue is described. Samples weighing 2-7 mg were digested by refluxing tissue in a mixture of perchloric and nitric acids, under conditions which minimized the hazards associated with perchloric acid digestion. In most tissues analyzed, reproducibility between triplicate samples was less than +/- 5%. However, where the amount of P in the tissue was very low (samples contained about 50 nmol P each), the variation between triplicates was greater.

Calcium↗
PubMed1984

Rapid enzymatic characterization of clinically encountered anaerobic bacteria with the API ZYM system.

The purpose of this study was to determine if enzyme profiles of anaerobic bacteria, obtained with the API ZYM system, are sufficiently distinctive and reproducible to merit future development of the system and an expanded data base for the four major groups of clinically encountered anaerobes. Of the total 155 clinical isolates and reference strains that were tested, 88% had distinctive patterns. It was possible to differentiate between 89% of the anaerobic gram-negative bacilli, 64% of anaerobic cocci, 100% of anaerobic gram-positive non-sporeforming bacilli and 100% of the Clostridium spp. using only the API ZYM plus Gram reaction, morphology and relation to oxygen. Overall reproducibility for 1,330 enzyme-substrate reactions was 97%. It was concluded that the API ZYM could be a practical system for rapid identification of clinical anaerobe isolates provided that an expanded data base is developed and that certain additional recommended tests are used.

Bacteria↗
PubMed1984

Stoma management.

Explore the source record for details and available documents.

Activities of Daily Living↗
PubMed1983

A factor analytic study of screening scales of adjudicated delinquent males and females.

Obtained a factor analysis of demographic and behavioral variables from self-ratings and observations of trained raters on a sample of 200 incarcerated delinquents, which resulted in eight identifiable factors with eigenvalues over 1.0. These were described as: The undersized youthful offender with emotional problems, the aggressive threatening offender, the drug subculture repeat offender, the neurotic polyabuse offender, the institutionally unadjusted offender, the bright offender, the immature neurotic offender, and the "established" psychopathic offender. Results provide understanding of the relationships and disparities between self-ratings, the ratings of others, and demographic variables.

Adolescent↗
PubMed1983

Decubitus ulcer prevention: a new investigative method using transcutaneous oxygen tension measurement.

Sacral skin oxygen tension, measured by a noninvasive technique in ten healthy subjects, remained in the normal range when they were lying on a "super-soft" mattress or in the 30 degrees lateral position. Therefore, these methods are effective in decubitus ulcer prevention. Skin oxygen tension measurement allows immediate assessment of the efficacy of measures to prevent decubitus ulcers.

Adolescent↗
PubMed1983

A double-blind clinical trial of iopamidol versus metrizamide for lumbosacral myelography.

A double-blind study was performed to compare metrizamide with the new iodinated water-soluble nonionic contrast medium, iopamidol, for conventional and computerized tomography lumbosacral myelography. Both contrast agents were used in 30 patients, and were equivalent in terms of image quality and clinical accuracy. Headaches and nausea were less severe using iopamidol. The most striking difference was found in adverse neurobehavioral reactions and associated electroencephalographic abnormalities, which were noted in 17% of the metrizamide group but were not seen with the use of iopamidol. Iopamidol appears to be superior to metrizamide for intrathecal applications. An explanation of the differential neurotoxicity is provided.

Clinical Trials as Topic↗
PubMed1983

A double-blind comparison of bupropion and amitriptyline in depressed inpatients.

Bupropion and amitriptyline were compared in a double-blind study of depressed inpatients. Treatment ranged from 2 to 4 weeks: early responders (Hamilton Depression Scale scores less than 10) were often removed from treatment after 2 or 3 weeks. Twenty-two patients completed treatment with bupropion and 18 with amitriptyline. Doses ranged from 450 to 750 mg/day for bupropion and 75 to 225 mg/day for amitriptyline. Overall, bupropion and amitriptyline were equally effective, as measured by the Hamilton Depression and Anxiety scales, Clinical Global Impressions, Zung Depression scale, and the SCL-90. Differences in the side effect profile and in weight change are described.

Adult↗
PubMed1982

Iopamidol vs metrizamide: a double blind study for cervical myelography.

A double-blind study was performed on 20 patients comparing the safety and efficacy of Iopamidol and Metrizamide in cervical myelography. The radiographic qualities of the Iopamidol and Metrizamide examinations were equivalent when using the same volume (12 to 13 ml), concentration (200 mg I/ml), and a C1-2 route of administration. The performance of a CT scan on selected patients in specified areas of interest provided additional diagnostic information in some patients (e.g syringomyelia, degenerative spondylosis). The adverse reactions were mild in the Iopamidol group with 4 of the 10 patients experiencing no adverse reactions. The more severe reactions, including disorientation, agitation, dysarthria, asterixis, hyperreflexia and EEG abnormalities were limited to the Metrizamide group with one or more occurring in 2 of the 10 patients studied. Only one Metrizamide patient experienced no adverse reactions. In this study containing a limited number of patients, Iopamidol was shown to be a diagnostically effective and safer contrast medium for performing cervical myelography.

Chemical Phenomena↗
PubMed1982

Inhibition of two mitochondrial enzymes by gold (III) halo complexes. Evidence for a binding mechanism.

Fumarase (EC 4.2.1.2) and mitochondrial L-malate dehydrogenase (EC 1.1.1.37) were both inhibited by NaAuCl4 and KAuBr4. The inhibition for both was measured as a function of gold complex concentration and aquation time, and the NaAuCl4 inhibition was also measured in the presence of 0.15 M NaCl. Regeneration of the enzyme activity after NaAuCl4 inhibition using L-cysteine, L-methionine and NaCN was also investigated. Sodium dodecyl sulfate (SDS) acrylamide gel electrophoresis and amino acid analysis was performed on the NaAuCl4 inhibited enzymes as well as on ribonuclease A (EC 3.1.26.2), lysozyme (EC 3.2.1.17) and liver alcohol dehydrogenase (EC 1.1.1.1). It was observed that the inhibition was proportional to the gold complex concentration but decreased markedly after aquation of the complex. In the presence of NaCl the initial rate of inactivation is essentially unaffected unless the complex has been aquated and then the initial rate is increased. Gel electrophoresis on gold complex-enzyme mixtures show polymerization for ribonuclease and lysozyme and amino acid analysis indicates that no oxidation has taken place. From these results, a binding mechanism is postulated for the inhibition of the dehydrogenases by direct displacement of a halide ligand, probably by two groups on the enzyme, at least one of which may be a sulfur containing acid.

Amino Acids↗