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Biomedical subjects

C E Miller

Publications and source records attributed to C E Miller.

At least 37 records · Page 2Linked to original sources

Stages of change theory and the nicotine-dependent client: direction for decision making in nursing practice.

Clinical practice is the basic purpose of nursing. Nursing's evolving professional development calls for the application of theory to direct decision making in nursing practice. Therefore, in an attempt to bridge what has been described as the "theory-practice gap," the author demonstrates how Prochaska and DiClemente's stages of change theory is relevant to nursing practice. According to Prochaska and DiClemente, behavioral change, such as smoking cessation, involves a process of five identified stages: precontemplation, contemplation, preparation, action, and maintenance. The author discusses each stage of change and the framework it provides for decision making in nursing practice. The concept of relapse is described and highlighted as a valuable learning experience. Finally, using the criteria set by Chinn and Kramer, systematic evaluation of the stages of change theory pinpoints strengths and discusses integration of the theory into nursing practice.

Adaptation, Psychological↗

On the antigenic determinants of the lipopolysaccharides of Vibrio cholerae O:1, serotypes Ogawa and Inaba.

Monoclonal, murine IgG1s S-20-4, A-20-6, and IgA 2D6, directed against Vibrio cholerae O:1 Ogawa-lipopolysaccharide exhibited the same fine specificities and similar affinities for the synthetic methyl alpha-glycosides of the (oligo)saccharide fragments mimicking the Ogawa O-polysaccharide (O-PS). They did not react with the corresponding synthetic fragments of Inaba O-PS. IgG1s S-20-4 and A-20-6 have absolute affinity constants for synthetic Ogawa mono- to hexasaccharides of from approximately 10(5) to approximately 10(6) M-1. For IgG1s S-20-4, A-20-6, and IgA 2D6, the nonreducing terminal residue of Ogawa O-PS is the dominant determinant, accounting for approximately 90% of the maximal binding energy shown by these antibodies. Binding studies of derivatives of the Ogawa monosaccharide and IgGs S-20-4 and A-20-6 revealed that the C-2 O-methyl group fits into a somewhat flexible antibody cavity and that hydrogen bonds involving the oxygen and, respectively, the OH at the 2- and 3-position of the sugar moiety as well as the 2'-position in the amide side chain are required. Monoclonal IgA ZAC-3 and IgG3 I-24-2 are specific for V. cholerae O:1 serotypes Ogawa/Inaba-LPS.1 The former did not show binding with members of either series of the synthetic ligands related to the O-antigens of the Ogawa or Inaba serotypes, in agreement with its reported specificity for the lipid/core region (1). Inhibition studies revealed that the binding of purified IgG3 I-24-2 to Ogawa-LPS might be mediated by a region in the junction of the OPS to the lipid-core region of the LPS. cDNA cloning and analysis of the anti-Ogawa antibodies S-20-4, A-20-6, and 2D6 revealed a very high degree of homology among the heavy chains. Among the light chains, no such homology between S-20-4 and A-20-6 on the one hand, and 2D6 on the other hand, exists. For the anti-Inaba/Ogawa antibodies I-24-2 and ZAC-3, their heavy chains are completely different, with some homology among the light chains.

Amino Acid Sequence↗

Binding of modified fragments of the Shigella dysenteriae type 1 O-specific polysaccharide to monoclonal IgM 3707 E9 and docking of the immunodeterminant to its modeled Fv.

The O-specific polysaccharide (O-SP) of Shigella dysenteriae type 1 has been shown by others to have the structure-->3)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->2)-alp ha-D- Galp-(1-->3)-alpha-D-GlcpNAc-(1-->. We have shown in the past that IgM 3707 E9, an anti S. dysenteriae type 1 O-SP monoclonal antibody, binds specifically to the -alpha-L-Rhap-(1-->2)-alpha-D-Galp-determinant of the polysaccharide. In this report we show that determinant to have hydrogen bonds, necessary for binding to the antibody, involving positions 3, 4 and 6 of the galactopyranosyl residue. The hydroxyl groups of the rhamnopyranosyl moiety of the immunodeterminant appear not to partake in hydrogen-bond interactions with the antibody. A model is presented of the Fv of IgM 3707 E9 based on our previously established cDNA-sequence and two known, highly homologous immunoglobulin crystal structures. The methyl glycoside of the immunodeterminant alpha-L-rhamnopyranosyl-(1-->2)-alpha-D-galactopyranose is docked to the combining area of the Fv.

Amino Acid Sequence↗

Developmental differences in response of mesenteric artery to acute hypoxia in vitro.

Studies were conducted to determine if the response of in vitro mesenteric artery from 3- and 35-day-old swine to acute hypoxia was age dependent. Isometric tension developed by mesenteric artery rings was measured using a standard myograph apparatus. When the buffer aeration gas was changed from 95% O2-5% CO2 to 95% N2-5% CO2, phenylephrine-precontracted rings from both age groups consistently demonstrated a triphasic response, consisting of, in order, an initial, brief dilation, a sharp contraction, and a sustained loss of tone. The only portion of the triphasic response that was age dependent was the constrictor response, hypoxic vasoconstriction (HVC), which was significantly greater in rings from younger animals. HVC appeared to be mediated by a hypoxia-induced loss of constitutive nitric oxide production. Thus HVC was eliminated by endothelial removal, significantly attenuated by pretreatment with NG-monomethyl-L-arginine (L-NMMA), but not with NG-monomethyl-D-arginine, restored by coadministration of L-arginine, and accentuated by pretreatment with superoxide dismutase. Blockade of endothelin A receptors with BQ-610 or inhibition of cyclooxygenase or lipoxygenase activities with indomethacin or phenidone had no effect on HVC in either group. HVC appeared to be dependent on reduction in PO2, not on reduced ATP secondary to hypoxia, as it did not occur in rings administered 2,4-dinitrophenol, an agent that uncouples oxidative phosphorylation. The magnitude of HVC, which appears to be mediated by hypoxia-induced supression of NO production, is greater in mesenteric artery from 3-day-old swine than from 35-day-old swine.

2,4-Dinitrophenol↗

Improving oral health for people with special needs through community-based dental care delivery systems.

A community-based dental care delivery system is described. This system has been used in a number of communities in California to improve oral health for people with special needs. It includes oral health assessment, coalition building, development and networking of local resources, training of dental professionals, and utilization of preventive dentistry training materials. Also discussed are challenges of the future that will need to be met to continue to make oral health a priority and reality for people with special needs in California.

Adolescent↗

Recovery of monoclonal antibody from its complex with ligand.

The separation of antibody from its excess and bound ligand is important following affinity chromatography or the use of methods requiring large amounts of antibody, such as microcalorimetry. Using radioactively labeled ligands we show that these separations can be effected by using commercially available, short polyacrylamide size-exclusion columns. By using both low (K alpha = 5 x 10(2) M-1) and medium high-affinity (K alpha = 0.6 x 10(6) M-1) ligands in the presence of antibody, it is shown that the latter system requires more dilute loading concentrations than the former system does in order to achieve acceptable separation. Since the degree of association between a protein and a ligand is solely governed by the affinity constant for the binding equilibrium, these results are applicable to any system represented by this range of binding constants.

Antibodies, Monoclonal↗

Risk factors for higher cost in congenital heart operations.

BACKGROUND: For many congenital heart defects, hospital mortality is no longer a sensitive parameter by which to measure outcome. Although hospital survival rates are now excellent for a wide variety of lesions, many patients require expensive and extensive hospital-based services during the perioperative period to enable their convalescence. These services can substantially increase the cost of care delivery. In today's managed care environment, it would be useful if risk factors for higher cost could be identified preoperatively so that appropriate resources could be made available for the care of these patients. The focus of this retrospective investigation is to determine if risk factors for high cost for repair of congenital heart defects can be identified. METHODS: We assessed financial risk by tracking actual hospital costs (not charges) for 144 patients undergoing repair of atrial septal defect (58 patients), ventricular septal defect (48 patients), atrioventricular canals (14 patients), or tetralogy of Fallot (24 patients) at Duke University Medical Center between July 1, 1992, and September 15, 1995. Furthermore, we were able to identify where the costs occurred within the hospital. Financial risk was defined as a large (> 60% of mean costs) standard deviation, which indicated unpredictability and variability in the treatment for a group of patients. RESULTS: Cost for atrial septal defect repair was predictably consistent (low standard deviation) and was related to hospital length of stay. There were factors, however, for ventricular septal defect, atrioventricular canal, and tetralogy of Fallot repair that are identifiable preoperatively that predict low- and high-risk groups using cost as an outcome parameter. Patients undergoing ventricular septal defect repair who were younger than 6 months of age at the time of repair, who required preoperative hospital stays of longer than 7 days before surgical repair, or who had Down's syndrome had a less predictable cost picture than patients undergoing ventricular septal defect repair who were older than 2 years, who had short (< 4 days) preoperative hospitalization, or who did not have Down's syndrome ($48,252 +/- $42,539 versus $15,819 +/- $7,219; p = 0.008). Patients with atrioventricular canals who had long preoperative hospitalization (> 7 days), usually due to pneumonia (respiratory syncytial virus) with preoperative mechanical ventilation had significantly higher cost than patients with atrioventricular canals who underwent elective repair with short preoperative hospitalization ($83,324 +/- $60,138 versus $26,904 +/- $5,384; p = 0.05). Patients with tetralogy of Fallot had higher costs if they had multiple congenital anomalies, previous palliation (combining costs of both surgical procedures and hospital stays), or severe "tet" spells at the time of presentation for operation compared with patients without these risk factors ($114,202 +/- $88,524 versus $22,241 +/- $7,071; p = 0.0005). One patient (with tetralogy of Fallot) with multiple congenital anomalies died 42 days after tetralogy of Fallot repair of sepsis after a gastrointestinal operation. Otherwise, hospital mortality was 0% for all groups. CONCLUSIONS: Low mortality and good long-term outcome for surgical correction of congenital heart defects is now commonplace, but can be expensive as some patients with complex problems receive the care necessary to survive. This study demonstrates that it is possible to identify factors preoperatively that predict financial risk. This knowledge may facilitate implementation of risk adjustments for managed care contracting and for strategic resource allocation.

Age Factors↗

Characterization of passive embryonic myocardium by quasi-linear viscoelasticity theory.

The mechanical properties of embryonic cardiac tissue, an important link between form and function, are largely unknown. This study provides new information on the viscoelastic behavior of the stage-16 and stage-18 (21/2 and 3 d) chick ventricle. The cylindrical ventricles were removed from the embryo, arrested in diastole, and mounted between two small wires in a specially designed experimental workstation. After preconditioning, ramp-and-hold stress relaxation tests were performed at 10, 20 and 40% stretch. The resulting reduced relaxation functions were fit by graphical approach with a quasi-linear viscoelastic representation. All functions were highly linear with natural log time between 1 and 60 s; mean slopes were -0.051 to -0.067. Other mean values were: fast time constant tau 1, 0.037-0.052 s; slow time constant tau 2, 296-486 s; and final relaxation G([symbol: see text]), 0.38-0.59. These results agree closely with those of adult tissue. The differences in parameters were not significant either between stretch levels within stage or between stages at the same stretch level. An extrapolation/renormalization procedure increased agreement in slope between stretch levels but decreased agreement in G([symbol: see text]). Events occurring on the short time scale may represent extracellular fluid filtration while final relaxation may be a function of true tissue viscoelasticity. These results will provide a baseline for extension to later developmental stages in cases of both normal and altered growth.

Animals↗

Passive stress-strain measurements in the stage-16 and stage-18 embryonic chick heart.

The first stress-strain measurements on embryonic cardiovascular tissue are described here, obtained from cyclic uniaxial loading of the primitive ventricle. An excised ventricular segment from Hamburger/Hamilton stage-16 or stage-18 chicks (2-1/2 and 3 days of a 21-day incubation period) was mounted longitudinally between two small wires in oxygenated Krebs-Henseleit cardioplegia solution. One wire was attached to an ultrasensitive force transducer and the other to a Huxley micromanipulator controlled by remote motor drive. A real-time video tracking system calculated three myocardial surface strains based on the positions of three surface markers while the heart was deformed in a triangular wave pattern. Force transducer output was filtered, digitally sampled, and stored with strains and time. Results were plotted as strain (longitudinal, circumferential, shear, and principal) versus time, stress versus time, and stress versus longitudinal strain. The stress-strain curves were nonlinear, even at low strain levels. The hysteresis loops were large; mean hysteresis energy as a proportion of total cycle stored strain energy was 36 percent (stage 16) and 41 percent (stage 18). We created a finite element model of the ventricle and fit the model behavior to the experimental behavior to determine parameters for a stage-18 pseudoelastic strain-energy function of exponential form. The calculated exponential parameter is significantly lower than that found in corresponding uniaxial studies of mature myocardium, possibly indicating the lower fiber content of the immature tissue. The results of this study are the first step in characterizing material properties for comparisons with later developmental stages and with impaired and altered myocardium. The long-term goal is to aid in identifying the biomechanical factors regulating growth and morphogenesis.

Animals↗

Novel compound tetra-, dinucleotide microsatellite polymorphism in the tumor necrosis factor/lymphotoxin locus.

A polymorphic (TGCG)n, tetranucleotide repeat was discovered juxtaposed to the (GT)n dinucleotide repeat that comprises the tumor necrosis factor a microsatellite (TNF) located telomeric to the tumor necrosis factor/lymphotoxin gene cluster. The degree of complexity of this compound tetra-,dinucleotide microsatellite consists of 16 potential alleles of combined length ranging from 24 to 54 bp. The pattern of frequencies of individual alleles belonging to the compound TNFa microsatellite was established from 52 healthy volunteers and was found to be highly heterogeneous. The data diverges significantly from previously published statistics that recognized only a simple variable dinucleotide tandem repeat. The newly recognized compound tetra-, dinucleotide TNFa microsatellite polymorphism establishes a more accurate genetic basis to explore potential linkage with disease susceptibility genes located within this region of the class III major histocompatibility complex. In addition, variable tumor necrosis factor and lymphotoxin production may reflect the more complex polymorphic nature of this microsatellite region. Finally, compound microsatellites probably exist elsewhere, throughout the human genome. Recognition of their presence may have a considerable impact on the validity of past and future microsatellite-based genetic analyses.

Base Sequence↗

Laparoscopic assisted vaginal hysterectomy of the large uterus using ultrasonic dissection.

Laparoscopic assisted vaginal hysterectomy (LAVH) is a procedure gaining in popularity over abdominal hysterectomy, for a number of different indications. According to a recent study by Wilcox, et al., over 1.7 million women underwent a hysterectomy procedure in the U.S. from 1988 through 1990, and two-thirds of the procedures for benign disease were performed for leiomyomata or endometriosis, indications typically afflicting women of child-bearing age. Seventy-five percent of the procedures included in the Wilcox study were abdominal hysterectomies, the remainder being vaginal hysterectomies. National Hospital Discharge Summary data reveal that 562,000 hysterectomies were performed in 1993, rendering hysterectomy second only to cesarean section in volume of annual Ob/Gyn surgical procedures performed.

Journal Article↗

Of four murine, anti-Shigella dysenteriae type 1 O-polysaccharide antibodies, three employ V-genes that differ extensively from those of the fourth.

Three murine, monoclonal antibodies, IgM 5286 F2, IgM 5297 C1, and IgG 5338 H4 were generated against Shigella dysenteriae type 1 O-specific polysaccharide (O-SP)-conjugate. They are specific for the O-SP, which is a poly-[alpha-L-rhamnopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-al pha-D-galactopyranosyl-(1-->3)-2-deoxy-2-amino-N-acetyl-alpha-D-glucopyr anosyl]. The VH and VL genes of these antibodies were cloned and their sequences determined. They showed 93% homology, but were quite different to the primary sequence of IgM 3707 E9, of the same O-SP-specificity, previously reported. The fine-specificities of both IgG 5338 H4 and IgM 3707 E9 were for the same disaccharide moiety in the O-SP, while IgMs 5286 F2 and 5297 C1 showed fine-specificity for the entire repeating unit of the O-SP. Therefore, divergent sequences can confer upon antibodies similar-, or even identical-carbohydrate-epitope fine-specificity. In addition, close primary sequence-homology does not preclude differences in antibody fine-specificity.

Amino Acid Sequence↗

Laparoscopic myomectomy in the infertile woman.

STUDY OBJECTIVE: To compare the outcome of the procedure we developed for laparoscopic myomectomy with outcomes reported in the literature for open and laparoscopic myomectomies. DESIGN: Prospective trial. SETTING: Lutheran General Hospital, Park Ridge, IL. PATIENTS: Forty-one consecutive infertile women who met selection criteria that were based on our experience with 15 initial laparoscopic myomectomies. INTERVENTION: Laparoscopic myomectomy. MEASUREMENTS AND MAIN RESULTS: Laparoscopic myomectomy was attempted in 41 and completed successfully in 40 women with minimal blood loss. Beyond the single conversion there were no major complications. The pregnancy rate within a year of the procedure was 75% (30 women) and viable term delivery rate was 65% (26 women). CONCLUSIONS: Pregnancy and viable term delivery rates compared favorably with those after open myomectomy procedures. Laparoscopic myomectomy was effective for selected patients experiencing infertility.

Female↗

The effects of systemic hypotension on postnatal intestinal hemodynamics and oxygenation.

This study investigated the effect of acute systemic hypotension, induced by pericardial tamponade, on intestinal hemodynamics and oxygenation in 3- and 35-d-old swine. To delineate intrinsic versus systemic responses, the effects of tamponade were compared with those noted after isolated pressure reduction to an innervated in vivo gut loop, achieved by local arterial constriction. Younger subjects demonstrated 16 and 58% increases in vascular resistance during constriction and tamponade, respectively, whereas older subjects exhibited an increase in resistance (27%) only during tamponade. Intestinal oxygen uptake decreased approximately 30% during both constriction and tamponade in the younger group, despite the greater effect of tamponade on gut perfusion. Older subjects exhibited no change in gut oxygenation during either perturbation. In a separate series of experiments, vasopressin, phenylephrine, and angiotensin II, each an element of the systemic pressor response, were infused into in vitro gut loops from 3- and 35-d-old swine. Vasopressin caused sustained vasoconstriction in both age groups; however, phenylephrine and angiotensin II caused greater sustained increases in intestinal vascular resistance in 3- than in 35-d-old intestine. We conclude that systemic hypotension compromises intestinal perfusion to a greater extent in younger subjects, although this effect is not associated with overwhelming tissue hypoxia. The pronounced rise in gut vascular resistance in 3-d-old intestine may reflect the additive effects of intrinsic and systemic vasoactive forces engaged during acute systemic hypotension.

Age Factors↗

Rapid purification of recombinant green fluorescent protein using the hydrophobic properties of an HPLC size-exclusion column.

The green fluorescent protein (GFP) of the jelly fish Aequoria victoria was cloned into an Escherichia coli cell line that is a methionine auxotroph. The recombinant GFP (rGFP) was isolated from the cells and purified using a simple procedure consisting of only two chromatographic steps: size-exclusion chromatography and ion-exchange HPLC. Due to the hydrophobic nature of the protein, the surface characteristics of the HPLC size column, and the high initial salt concentration, the rGFP sticks to the size column and is eluted by reducing the salt concentration. Due to this unique behavior the purification procedure can readily be scaled to handle larger quantities of rGFP.

Animals↗

Incisional bowel herniations after operative laparoscopy: a series of nineteen cases and review of the literature.

OBJECTIVES: The objectives of this report were (1) to identify all cases of incisional bowel herniations noted after operative laparoscopy in 11 participating institutions and (2) to report the clinical details of such patients. STUDY DESIGN: A retrospective case review was performed. RESULTS: Nineteen cases of incisional bowel herniation were identified. The average age of the patients was 50.5 years. Initial laparoscopic procedures varied and included laparoscopically assisted vaginal hysterectomy (six patients), laparoscopically assisted vaginal hysterectomy with lymphadenectomy (five patients), oophorectomy (two patients), adhesiolysis (two patients), myomectomy (two patients), lymphadenectomy alone (one patient), and ovarian cystectomy (one patient). The average time to reoperation was 8.5 days. CONCLUSIONS: Incisional bowel herniation is a serious complication of operative laparoscopy. Herniations occur through ports > or = mm in size at both umbilical and extraumbilical sites. New techniques are needed to avoid this serious complication.

Adult↗