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Biomedical subjects

C L Hansen

Publications and source records attributed to C L Hansen.

At least 37 records · Page 2Linked to original sources
PubMed1993

Production of ultrafiltered skim milk retentate powder. 1. Composition and physical properties.

Raw skim milk retentate with 20% solids produced by UF was subjected to different heat treatments and pH adjustments prior to spray-drying. The heat treatments were 65 degrees C for 30 min, 75 degrees C for 28 s, and 85 degrees C for 28 s. pH was adjusted to 6.4, 6.7, and 7.0. Retentate powders were analyzed for moisture, protein, lactose, fat, ash, titratable acidity, and pH. Physical property determinations included solubility index, dispersibility, viscosity, scorched particles, poured density, packed density, and water absorption isotherm. No interaction effects of heat treatment and pH adjustment were observed. pH adjustments affected ash content and solution viscosity. Heat treatment affected solubility and poured density. pH adjustments and heat treatment had only minor effects on the measured properties.

Animals↗
PubMed1992

Metal thiolate coordination in the E7 proteins of human papilloma virus 16 and cottontail rabbit papilloma virus as expressed in Escherichia coli.

The oncogenic E7 proteins of human papilloma virus (HPV 16) and of cottontail rabbit papilloma virus (CRPV) have been purified from an expression system in Escherichia coli. The proteins as purified from E. coli contain one tightly bound Zn(II) ion per molecule. The metal site shows facile exchange with either Cd(II) or Cu(I). The HPV 16 E7 maximally bound one Cd(II) or two Cu(I) ions, while the CRPV E7 bound two Cd(II) or three Cu(I) ions. The Cd(II) and Cu(I) E7 molecules exhibited optical transitions in the ultraviolet suggestive of metal:thiolate coordination. E7 proteins from HPV 16 and CRPV contain 7 and 8 cysteines/molecule, respectively. Reaction of the E7 proteins with the sulfhydryl reagent, dithiodipyridine, revealed that all the cysteinyl sulfurs are present in the reduced thiol state. Cu(I)-E7 molecules are luminescent with maximal emission at 570 nm. The observed emission at room temperature is indicative of metal coordination within a compact protein environment shielded from solvent interactions. The emission maxima occurs at the same wavelength (570 nm) as Cu(I)-cysteinyl sulfur clusters in Cu(I)-metallothioneins. The single Zn(II) atom in each protein can be removed from E7 in the presence of EDTA. The resulting apoE7 molecules remain soluble and can be partially reconstituted with Cd(II) to regain the ultraviolet charge transfer transitions.

Animals↗
PubMed1992

Attenuation correction of thallium SPECT using differential attenuation of thallium photons.

The greatest limitation of 201Tl for the diagnosis of coronary artery disease remains the high soft-tissue attenuation of its low energy photons. However, thallium also emits a smaller number of higher energy photons. Since photons of higher energy undergo less attenuation, it was postulated that the amount of attenuation could be ascertained from the ratio of the low-to-high energy photon counts. A planar phantom was used to derive a regression equation relating attenuation to the count ratio of the low and high energy peaks. A three-dimensional heart phantom was constructed and SPECT images were obtained in air and water. Application of the attenuation correction algorithm to the SPECT images of the phantom in water produced images quantitatively similar to that obtained in air. We conclude that by using differential photon attenuation, correction of 201Tl SPECT using a single order post-processing technique is feasible. This technique may allow for more accurate analysis of thallium myocardial perfusion scintigraphy.

Heart↗
PubMed1991

The interaction between aspartic acid 237 and lysine 358 in the lactose carrier of Escherichia coli.

The lacY from Escherichia coli strains 020 and AE43 have been cloned on plasmids which were designated p020-K358T and pAE43-D237N. These lacY mutants contain amino acid substitutions changing Lys-358 to Thr or Asp-237 to Asn, respectively. The charge neutralizing effect of each mutation is associated with a functional defect in melibiose transport which we exploited in order to isolate second site revertants to the melibiose-positive phenotype. Eleven melibiose-positive revertants of p020-K358T were isolated. All contained a second-site mutation converting Asp-237 to a neutral amino acid (8 to Asn, 1 to Gly, and 2 to Tyr). Twelve melibiose-positive revertants of pAE43-D237N were isolated. Two were second-site revertants converting Lys-358 to a neutrally Gln residue, while the remainder directly reverted Asn-237 to the wild-type Asp-237. We conclude that the functional intimate relationship between Asp-237 and Lys-358 suggests that these residues may be closely juxtaposed in three-dimensional space, possibly forming a 'charge-neutralizing' salt bridge.

Amino Acid Sequence↗
PubMed1991

Role changes at the pharmacy-nursing interface: Kimball Medical Center.

The original goals and objectives of the CST program have been realized. Medication safety, control, accountability, and utilization efforts of decentralized satellite pharmacists have been brought to fruition. A career ladder has been created for the pharmacy technician. This has enabled the Department of Pharmaceutical Services to recruit, retain, and develop an exceptionally competent and proficient technical staff. The pharmacy has earned a new found respect from the nursing division. A greater awareness of its staff's positions as drug experts and information resources has evolved. Credibility has been established for additional pharmacy programs and proposed clinical activities. Pharmacists and technicians have gained an in-depth understanding of the procedures, problems, and challenges of the nursing services, which has enabled a bridge of understanding and a common bond of team effort to be built between the two departments.

Hospital Bed Capacity, 300 to 499↗
PubMed1990

Lactose transport mutants of Escherichia coli resistant to inhibition by the phosphotransferase system.

The lactose carrier activity of Escherichia coli is inhibited by the binding of dephosphorylated glucose enzyme III. Saier et al. ((1978) J. Bacteriol. 133, 1358-1367) isolated lacY mutants that escaped this inhibition. This communication reports the cloning and sequencing of one of the Saier mutants and the isolation, cloning and sequencing of another similar mutant. Both mutations resulted in amino acid substitutions on the middle cytoplasmic loop of the carrier (alanine-198 to valine and serine-209 to isoleucine). It is concluded that this cytoplasmic loop may be one of the sites of binding of glucose enzyme III.

Binding Sites↗
PubMed1990

[Anesthesiologic aspects of narco-curare-electroshock treatment].

The physiology and side-effects of narco-curare-electric shock treatment are reviewed on the basis of the literature and, similarly, risk groups are delimited. Directives for preoperative assessment, the anaesthesiological procedure and per- and postoperative observation are given. It is concluded that the NCE procedure is associated with a low risk and slight mortality provided the above-mentioned conditions are observed. Patients with cardiovascular disease constitute the greatest risk group and should receive optimal medical treatment prior to NCE. In cases with raised intracranial pressure, NCE should only be employed with great reservation. ECG monitoring, treatment with atropine and preliminary treatment with oxygen are advised in general. Withdrawal of psychocopharmaca prior to NCE is rarely indicated.

Anesthesia, General↗
PubMed1990

Production of anticardiolipin antibodies by cultured human lymphocytes.

Antibodies against negatively charged phospholipids, such as those to cardiolipin, can often be detected in the serum of patients with autoimmune related conditions, chronic infections and in patients treated with phenothiazines. In the present study, peripheral blood lymphocytes from nine healthy controls and eight patients with phenothiazine-induced IgM anticardiolipin antibodies (ACA) and the lupus anticoagulant were placed in vitro. Culture supernatants were assayed for ACA by measurement of optical densities using an ELISA. A significant difference (p less than 0.05) was demonstrated between the mean concentration of culture supernatant ACA from the patients as compared to healthy controls. The concentration of ACA in culture supernatants strongly correlated (r = 0.85) with that from the serum. There was a weak correlation between serum and culture supernatant ACA concentration and the lupus anticoagulant activity as measured by prolongation of the partial thromboplastin time. This technique uses readily accessible peripheral blood lymphocytes and should permit dissection of cytokine and cellular immune pathways regulating APA production.

Antiphospholipid Syndrome↗
PubMed1990

Autoimmune MRL-1 pr/1pr mice are an animal model for the secondary antiphospholipid syndrome.

Patients with systemic lupus erythematosus often develop thrombosis, recurrent abortion, thrombocytopenia and neurological disease, in association with serum antibodies against phospholipids, termed the secondary antiphospholipid syndrome. In our search for an animal model for the human antiphospholipid syndrome, we examined the MRL-1pr/pr mouse, which develops a lupus-like illness. These mice were found to have significantly elevated levels of serum antiphospholipid antibodies (aPL) and thrombocytopenia compared to normal mice. By immunodiffusion, these antibodies are similar to human aPL. We observed histologic evidence of central nervous system thromboses as well as perivascular infiltrates of the choroid plexus. The high titers of serum aPL, thrombocytopenia, and thrombosis establish this strain as an animal model for the secondary antiphospholipid syndrome.

Animals↗
PubMed1989

Bartter's syndrome--treatment with potassium, spironolactone and ACE-inhibitor.

The treatment of Bartter's syndrome is fraught with difficulties, and there is no consensus concerning the pathogenetic mechanisms involved. Potassium depletion with hypokaliaemia is a dominant feature of the syndrome. In this case history, a 42-year-old woman suffering from Bartter's syndrome did not improve on several therapeutic trials. An impressive progress was noted, however, after intensive potassium repletion with subsequent potassium/spironolactone/ACE-inhibitor treatment. After 24 months her condition was unchanged with normal and stable Se-potassium concentration.

Adult↗
PubMed1988

Abnormal myocardial fatty acid metabolism in dilated cardiomyopathy detected by iodine-123 phenylpentadecanoic acid and tomographic imaging.

The radioidinated synthetic fatty acid iodine-123 phenylpentadecanoic acid (IPPA) has proven useful in the identification of regional abnormalities of cardiac metabolism in patients with myocardial ischemia. The present study was performed to test the hypothesis that the myocardial distribution and turnover of fatty acids, assessed noninvasively with IPPA, are altered in patients with cardiomyopathy. Nine normal volunteers and 19 patients with dilated cardiomyopathy of various etiologies underwent cardiac imaging with single-photon emission computed tomography (SPECT) after intravenous injection of IPPA. Apical short-axis and basal short-axis sections were reconstructed and quantitatively analyzed for relative IPPA activity distribution and washout. Patients with congestive cardiomyopathy demonstrated significantly greater heterogeneity of IPPA uptake than normal subjects (maximal percent variation of activity 27 +/- 11 vs 18 +/- 4, p less than 0.01). They also demonstrated a more rapid percent washout rate than control subjects (24 +/- 8 vs 17 +/- 6 for the apical short-axis section, p less than 0.05; 26 +/- 7 vs 18 +/- 5 for the basal short-axis section, p less than 0.01). These abnormalities of fatty acid distribution and turnover were independent of the etiology of the cardiomyopathy. The degree of heterogeneity of IPPA uptake was significantly related to the patients' New York Heart Association functional class (r = 0.64, p less than 0.01). Thus, compared with normal myocardium, the myocardium of patients with congestive cardiomyopathy demonstrates a more heterogeneous distribution of fatty acid uptake, which parallels the clinical severity of the disease. Furthermore, patients with congestive cardiomyopathy demonstrate a more rapid myocardial clearance of the labeled fatty acid, as assessed with SPECT imaging.

Adult↗
PubMed1988

Iodine-123 phenylpentadecanoic acid and single photon emission computed tomography in identifying left ventricular regional metabolic abnormalities in patients with coronary heart disease: comparison with thallium-201 myocardial tomography.

Iodine-123 phenylpentadecanoic acid (IPPA) is a synthetic long chain fatty acid with myocardial kinetics similar to palmitate. Two hypotheses were tested in this study. The first hypothesis was that IPPA imaging with single photon emission computed tomography (SPECT) is useful in the identification of patients with coronary artery disease. Fourteen normal volunteers (aged 27 +/- 2 years) and 33 patients (aged 54 +/- 11 years) with stable symptomatic coronary artery disease and at least one major coronary artery with luminal diameter narrowing greater than or equal to 70% were studied with symptom-limited maximal exercise testing. The IPPA (6 to 8 mCi) was injected 1 min before the termination of exercise, and tomographic imaging was performed beginning at 9 min and repeated at 40 min after the injection of IPPA. Nine of the normal volunteers and 13 of the patients had a second examination performed at rest on another day. Using the limits of normal as 2 SD from the normal mean values, 27 of the 33 patients with coronary artery disease demonstrated abnormalities in either the initial distribution or the clearance of IPPA, or both. Nineteen of the 33 patients had a maximal variation of activity distribution of greater than or equal to 25% on the 9 min IPPA images. Twenty-two of the 33 patients had a maximal variation in IPPA washout greater than 17% and 17 had a washout rate less than or equal to 2%. There was good agreement between the location of significant coronary artery stenoses and abnormalities in the initial distribution and clearance of IPPA. The second hypothesis tested was that IPPA imaging is as or more sensitive and, therefore, complementary to thallium-201 imaging in the identification of exercise-induced ischemia in patients. Twenty-five of the 33 patients underwent both thallium-201 and IPPA tomographic imaging after symptom-limited maximal exercise testing. The amount of exercise performed by each patient during both studies was similar. Twenty-one of the 25 patients had abnormal IPPA tomographic studies, whereas 18 had abnormal thallium-201 tomographic studies (p = NS). The results of this study suggest the following conclusions: 1) iodine-123 phenylpentadecanoic acid imaging using single photon emission computed tomography and exercise provides a sensitive and relatively noninvasive method for identifying abnormalities in myocardial metabolism associated with significant coronary artery stenoses, and 2) iodine-123 phenylpentadecanoic acid is at least as sensitive as thallium-201 for this purpose using tomographic imaging and exercise testing.

Adult↗
PubMed1986

Iodine 123-phenylpentadecanoic acid myocardial scintigraphy: usefulness in the identification of myocardial ischemia.

In this study, we tested the hypothesis that myocardial ischemia induced by exercise in patients is associated with diminished metabolism and/or delayed clearance of an intravenously injected fatty acid, iodine 123-labeled phenylpentadecanoic acid (IPPA). Fifteen normal volunteers and 18 patients with significant coronary heart disease (CHD) received IPPA during exercise. In the patients with CHD, radionuclide ventriculograms were also obtained during exercise. The normal volunteers had relatively uniform initial left ventricular segmental IPPA activity after exercise and uniform IPPA clearance in the interval from 4 to 20 min immediately after exercise. In contrast, the patients with CHD had increased initial left ventricular segmental IPPA activity (63%, p less than .001) and delayed IPPA clearance (44%, p less than .01) in segments supplied by significantly narrowed coronary arteries. Based on analysis with the mean values +/- 1 SD for initial IPPA activity, clearance, or both in normal volunteers, the sensitivity and specificity of exercise IPPA scintigraphy for detecting CHD were 89% and 67%, respectively; when +/- 2 SD differences from the mean values in the normal volunteers were considered, the sensitivity and specificity were 72% and 100%, respectively. Among the total of 27 noninfarcted left ventricular segments supplied by significantly narrowed coronary arteries in the study patients, 26 (96%) had an abnormality (mean +/- 1 SD) of either initial IPPA activity or clearance compared with corresponding segments in the normal volunteers and/or with other left ventricular segments in the same image that were not supplied by significantly narrowed coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

The "hurricane sign": evidence of patient motion artifact on cardiac single-photon emission computed tomographic imaging.

Single-photon emission computed tomography (SPECT) is frequently used with myocardial perfusion imaging in the assessment of patients with known or suspected coronary artery disease. The susceptibility of SPECT imaging to artifact, especially that caused by patient motion, has long been recognized. We report a characteristic artifact of patient motion, which we have termed the "hurricane sign" because of its similarity to the National Weather Service Symbol for a hurricane. This artifact is caused by varying contributions of different portions of the heart during image acquisition and their misalignment produced by patient motion.

Artifacts↗