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Biomedical subjects

M Lewis

Publications and source records attributed to M Lewis.

At least 397 records · Page 22Linked to original sources
PubMed1986

Aortic root abscess. Initial experience using magnetic resonance imaging.

The detection of aortic root abscess by magnetic resonance imaging has not been described previously. We report a patient with an aortic root abscess that was successfully diagnosed by magnetic resonance imaging and echocardiography. Computed tomography failed to detect the abscess. The patient recovered with antibiotic therapy. Based on this case and other reports in the literature, we advocate treating similar patients without surgery. We recommend magnetic resonance imaging as an investigational method where the diagnosis of aortic root abscess is ambiguous.

Abscess↗
PubMed1986

Streptozocin diabetes alters immunoreactive beta-endorphin levels and pain perception after 8 wk in female rats.

Plasma, pituitary, and hypothalamic levels of the endogenous opioid peptide beta-endorphin were measured by radioimmunoassay and column chromatography in female rats 8 wk after the induction of diabetes with streptozocin (STZ) and in control female rats. In addition, pain perception was determined by measuring the latency to paw lick or jump after being placed on a hot plate. Plasma levels of immunoreactive beta-endorphin (IR-BE) were significantly reduced in STZ-induced diabetic female rats, as were the content and concentration of IR-BE in the neurointermediate lobe of the pituitary (NIL) and the content of IR-BE in the hypothalamus. The concentration but not the content of IR-BE in the anterior pituitary (AP) of the STZ-induced diabetic rats was increased significantly. Streptozocin-induced diabetes also resulted in a significant reduction in the total protein content of the AP, NIL, and hypothalamus. Column chromatography indicated that the decrease in IR-BE in the plasma, NIL, and hypothalamus represented a decrease in beta-endorphin, whereas the increase in IR-BE in the AP represented an increase in both beta-endorphin and beta-lipotropin. Diabetic animals consistently showed decreased latencies to paw lick or jump when subjected to hot-plate testing after 7 wk. These findings suggest that in female rats, central and peripheral endogenous opiate levels and tolerance to nociceptive thermal stimulation were diminished by 8 wk of chemically induced diabetes.

Animals↗
PubMed1985

Fractal surfaces of proteins.

Fractal surfaces can be used to characterize the roughness or irregularity of protein surfaces. The degree of irregularity of a surface may be described by the fractal dimension D. For protein surfaces defined with probes in the range of 1.0 to 3.5 angstroms in radius, D is approximately 2.4 or intermediate between the value for a completely smooth surface (D = 2) and that for a completely space-filling surface (D = 3). Individual regions of proteins show considerable variation in D. These variations may be related to structural features such as active sites and subunit interfaces, suggesting that surface texture may be a factor influencing molecular interactions.

Carboxypeptidases↗
PubMed1985

Cervical Chlamydia trachomatis infection in university women: relationship to history, contraception, ectopy, and cervicitis.

Endocervical Chlamydia trachomatis infection was found in 13 of 162 volunteer female university students (8%). Infection was correlated with younger age (p less than 0.05), less than or equal to 4 years of intercourse (p less than 0.05), a history of gonorrhea (p less than 0.01), and exposure to a partner with urethritis (p less than 0.01). Women who used intrauterine or barrier contraception had less infection (2%) than did women who used oral contraception (14.3%, p less than 0.05) or none at all (10.7%, p less than 0.05). Infection was strongly associated with a cervicitis score calculated from erythema, ectopy, discharge, and secretions that contained white blood cells (p less than 0.0001). By multivariate analysis, a proposed clinical approach was arrived at for testing for chlamydial organisms all women with cervicitis who were not using barrier contraception. The positive predictive value of this approach for chlamydial infection was 28%, and the negative predictive value 98.4%. Cervical ectopy was increased in women who used oral contraception (p less than 0.01), and infection was increased in women with ectopy, regardless of their contraceptive method (p less than 0.001). These results will aid in more rapid diagnosis of endocervical chlamydial infection and in the choice of contraception in young women and high-prevalence groups.

Adolescent↗
PubMed1985

Determination by high-performance liquid chromatography of some compounds involved in the biosynthesis of penicillin and cephalosporin.

A sensitive and convenient method for the simultaneous determination of several of the compounds involved in the biosynthesis of penicillin and cephalosporin is described. The method involves derivatization with a chiral fluorogen (o-phthaldialdehyde with an optically active thiol N-acetyl-L-cysteine), followed by high-performance liquid chromatography on a reverse-phase column as described by Aswad (D. W. Aswad, 1984, Anal. Biochem. 137, 405-409). With an analysis time of 1 h it was possible to determine simultaneously most of the common L-amino acids, L- and D-alpha-aminoadipic acid, L- and D-valine, delta-(L-alpha-aminoadipyl)-L-cysteine (AC), delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (ACV), glutathione, isopenicillin N, penicillin N, desacetoxycephalosporin C, desacetylcephalosporin C, and cephalosporin C. Using o-phthaldialdehyde alone it was possible to determine specifically the thiol-containing peptides AC, ACV, and glutathione.

Acetylcysteine↗
PubMed1985

Illnesses in infants born to women with Chlamydia trachomatis infection. A prospective study.

Chlamydia trachomatis is known to cause infant pneumonitis and conjunctivitis and is a suspected cause of otitis media and gastroenteritis. To identify infections associated with exposure to C trachomatis, infant illnesses were studied through a "blinded" review of medical records of 244 infants born to women cultured antenatally for cervical C trachomatis, 25% of whom had C trachomatis-positive cultures. Compared with unexposed infants, infants exposed to C trachomatis had twice the rate of both pneumonitis and recurrent otitis media in the first six months. Infants who were exposed to C trachomatis and who had pneumonitis had higher subsequent rates of gastroenteritis than either unexposed infants or exposed infants without pneumonitis. These results suggest that appreciable outpatient infant morbidity may be associated with maternal infection with C trachomatis, and that it may either cause or promote the occurrence of early, recurrent otitis media and gastroenteritis.

Bronchitis↗
PubMed1985

Multiplicity of genetic polymorphisms of blood in the Schmiedeleut Hutterites.

Ninety-eight alleles in 38 polymorphisms of blood are identified in the Schmiedeleut Hutterites. The study was initiated because of the presence of Wda, an allele found almost exclusively in Hutterites. Eight of the other alleles also have an exceedingly low incidence in a random white population: r'' (.006), R2w (less than .001), LWb (less than .01), ESD*rare (less than .001), GPT*0 (.004), NP*4 (less than .001), GOT2*3 (.001), and C6*0 (.002). The occurrence of this many rare alleles in a population with an estimated maximum of 124 ancestral genomes was surprising but consistent with observations in other isolates. The degree of heterozygosity and large family size make the population ideal for genetic linkage studies.

Blood Group Antigens↗
PubMed1985

Severe deficiency of alpha 1-antitrypsin associated with cutaneous vasculitis, rapidly progressive glomerulonephritis, and colitis.

The association of vasculitis with severe deficiency of alpha 1-antitrypsin is rare. This report describes a 44-year-old man with severe deficiency of alpha 1-antitrypsin associated with diffuse vasculitis involving skin, kidney (rapidly progressive glomerulonephritis), and colon (colitis). Colitis has not previously been reported in association with deficiency of alpha 1-antitrypsin. Other reported cases are reviewed and the possible immunologic mechanisms underlying the association are discussed.

Adult↗
PubMed1985

An enzyme-linked immunoassay for the detection of antibodies to endoplasmic reticulum.

A simple, sensitive solid-phase assay for the detection of antibodies to endoplasmic reticulum is described. The assay is dependent upon the amount of antigen bound to the solid support and upon the amount of antibody bound to the support via the relevant antigen. The assay can be used to measure both polyclonal and monoclonal antibody to endoplasmic reticulum. It has been used to isolate several monoclonal antibodies which can recognize and precipitate specific proteins of the endoplasmic reticulum. In addition, it has been used to probe the membrane orientation of endoplasmic reticulum antigens.

Animals↗
PubMed1985

Cloning and characterization of a nonmuscle myosin heavy chain cDNA.

Despite many biochemical and structural similarities between muscle and nonmuscle myosins, their genes appear to have completely diverged, since muscle myosin molecular clones will not hybridize to RNA from nonmuscle sources. Here we report the isolation and characterization of a partial myosin heavy chain (MHC) cDNA clone from the slime mold Dictyostelium discoideum. We have isolated this clone from a lambda gt11 expression cDNA library by antibody screening. In contrast to the highly conserved sarcomeric muscle MHC multigene families in other organisms, there appears to be only one gene encoding MHC in the Dictyostelium genome. The cloned portion of this gene does not hybridize to the genomic DNAs of other eukaryotic organisms. Analysis of the predicted amino acid sequence of the partial Dictyostelium MHC clone shows that while there is no sequence homology to known striated muscle MHCs, the structure- and coiled-coil-forming capacities have been conserved.

Amino Acid Sequence↗
PubMed1985

Maternal and neonatal responses related to the volatile agent used to maintain anaesthesia at caesarean section.

A standardized technique of general anaesthesia, with one randomly selected variable, was provided for 237 patients undergoing elective and 540 undergoing emergency Caesarean section. The variable was the volatile agent used to maintain anaesthesia, the choice resting between trichloroethylene (0.2 or 0.3 vol.%) and halothane (0.2, 0.3, 0.4 or 0.5 vol.%). No association was found between the type of agent and the duration of anaesthesia, or the duration of either the I-D or the U-D interval. A smaller total dose of suxamethonium was administered in conjunction with the higher concentrations of volatile agent. A statistically significant but clinically unimportant increase in the time elapsing from the cessation of anaesthesia to maternal achievement of a "safe level of consciousness" was found with the higher concentrations. The incidence of maternal awareness plus unpleasant dreams was unacceptably high when the lower concentrations were used, and it is recommended that either trichloroethylene 0.3 vol.% or halothane 0.4 or 0.5 vol.% be used. Neither agent, at these concentrations, was associated with neonatal depression in group A elective sections in which the fetus presented by the vertex, and although there was a possible tendency for their use in cases of fetal compromise to be associated with an increase in the incidence of neonatal respiratory depression, the degree of depression was of little consequence to neonatal well-being. It was confirmed that breech presentation and prolongation of the U-D interval are important determinants of depression and birth asphyxia among infants delivered by Caesarean section under general anaesthesia.

Anesthesia, General↗