Biomedical subjects

D Johnson

Publications and source records attributed to D Johnson.

At least 271 records · Page 15Linked to original sources

PubMed1997

Screening for domestic violence in a rural family practice.

This study evaluates the effectiveness of a screening form used to assess the incidence of current and past domestic abuse among patients seen in a rural family practice. Two of nine family physicians screened most adult women they saw at a rural primary care clinic for three months in early 1996. Of the 280 women who completed surveys, 94(34%) reported experiencing physical or emotional abuse at some time in the past. Twenty-three (8%) reported physical abuse within the past year. Fourteen women (5%) reported being currently afraid of their partner or someone else. Although current or past abuse was seen across all groups, women reporting abuse were more likely to be unmarried, younger, and on medical assistance. They were also more likely to have children at home. We concluded that the prevalence of women reporting current abuse in a rural family practice is sufficient to warrant mass screening.

Adult↗

PubMed1996

Acute lung injury fibroblast migration and invasion of a fibrin matrix is mediated by CD44.

Fibrosis results when myofibroblasts invade the wound fibrin provisional matrix. Extracellular matrix receptors on the cell surface mediate cell adhesion, migration, and invasion. Recent work with transformed cells indicates that these cells use the cell surface matrix receptor CD44 for migration and invasion. In this study, we examine whether lung fibroblasts, isolated from patients dying with acute alveolar fibrosis, use CD44 to invade a fibrin matrix. Consistent with a role for CD44 in mediating fibroblast invasion and subsequent tissue fibrosis, immunohistochemical analysis of lung tissue from patients who died from acute alveolar fibrosis after lung injury reveals CD44-expressing mesenchymal cells throughout newly formed fibrotic tissue. PCR, Western, and immunoprecipitation analysis demonstrate that the 85-kD CD44 isoform is expressed by acute lung injury fibroblasts. Consistent with a role in mediating matrix adhesion and migration ultrastructurally, CD44 was found uniformly over the cell surface and was found densely labeling filopodia and lamellipodia, highly motile structures involved in cell migration. To determine if lung injury fibroblasts use CD44 to invade fibrin, a fibrin gel model of fibrosis was used. By blocking the function of CD44 with monoclonal antibodies, fibroblast invasion into a fibrin matrix was inhibited. To examine the mechanism by which CD44 mediates fibroblast invasion, the role of CD44 in fibroblast migration and adhesion was evaluated. Anti-CD44 antibody blocked fibroblast migration on the provisional matrix proteins fibronectin, fibrinogen, and hyaluronic acid. Additionally, fibroblast CD44 mediated adhesion to the provisional matrix proteins fibronectin, fibrin, and hyaluronic acid, but not to laminin, a component of the basement membrane. These findings support the hypothesis that fibroblast CD44 functions as an adhesion receptor for provisional matrix proteins and is capable of mediating fibroblast migration and invasion of the wound provisional matrix resulting in the formation of fibrotic tissue.

Cell Adhesion↗

PubMed1996

A deubiquitinating enzyme interacts with SIR4 and regulates silencing in S. cerevisiae.

The SIR2, SIR3, and SIR4 proteins are required for silencing of transcription at the silent mating type loci and at telomeres in yeast. Using protein affinity chromatography, we show that SIR2, SIR3, and two proteins of 69 and 110 kDa tightly associate with SIR4. Surprisingly, the 110 kDa SIR4-binding protein is identical to UBP3, one of several previously described yeast enzymes that deubiquitinate target proteins. Deletion of the UBP3 gene results in markedly improved silencing of genes inserted either near a telomere or at one of the silent mating type loci, indicating that UBP3 is an inhibitor of silencing. We discuss possible roles for UBP3 in controlling the activity or assembly of the SIR protein complex.

Amino Acid Sequence↗

PubMed1996

Management of thyroid carcinoma with radioactive 131I.

PURPOSE: To evaluate the role of radioactive 131I in the management of patients with well differentiated carcinoma of the thyroid. METHODS AND MATERIALS: Between 1965 and 1995, a total of 117 patients with well-differentiated carcinoma of the thyroid underwent either lobectomy or thyroidectomy followed by 100-150 mCi of 131I. RESULTS: With a median follow-up of 8 years, only four patients (3%) developed a recurrence of their disease. The 5-year actuarial survival was 97% with a 10-year survival of 91%. There were no severe side effects noted after 131I therapy. CONCLUSIONS: Radioactive 131I is a safe and effective procedure for the majority of patients with well-differentiated thyroid carcinoma. We currently recommend that all patients undergo a subtotal or total thyroidectomy followed by 131I thyroid scanning approximately 4 weeks after surgery. If the thyroid scan shows no residual uptake and all disease is confined to the thyroid, we recommend following patients with annual thyroid scans and serum thyroglobulin levels. If there is any residual uptake detected in the neck or if the tumor extends beyond the thyroid, we recommend routine thyroid ablation of 100-150 mCi of radioactive 131I.

Adolescent↗

PubMed1996

The cloned rat pancreatic polypeptide receptor exhibits profound differences to the orthologous receptor.

Pancreatic polypeptide (PP) is produced in the islets of Langerhans and released in response to meals. It belongs to a family of peptides that also includes neuropeptide Y and peptide YY. In the present communication, we describe a rat receptor with high affinity for PP, therefore named PP1. Clones for the PP1 receptor were obtained by PCR using sequence information for the neuropeptide Y receptor Y1 from several species. The PP1 receptor has 46% overall amino acid sequence identity to the rat Y1 receptor and 56% identity in the transmembrane regions. The PP1 receptor displays a pharmacological profile that is distinct from previously described neuropeptide Y-family receptors. In competition with iodinated bovine PP, it binds rat PP with an affinity (K(i)) of 0.017 nM, while the affinities for peptide YY and neuropeptide Y are substantially lower with K(i) values of 162 and 192 nM, respectively. In stably transfected CHO cells, the PP1 receptor inhibits forskolin-stimulated cAMP synthesis. Northern blot hybridizations to a panel of mRNAs detected transcripts in testis and lung. A faint band was seen in colon and total brain. In contrast, the human receptor is expressed primarily in colon and small intestine. Whereas rat and human PP1 bind PP with the same affinity, the rat receptor has much lower affinity than its human ortholog for peptide YY and neuropeptide Y. Interestingly, the amino acid sequence identity between rat and human PP1 is only 75%. Thus, the sequence, the tissue distribution, and the binding profile of the PP1 receptor differ considerably between rat and human.

Amino Acid Sequence↗

PubMed1996

The diagnosis and treatment of gastroesophageal reflux disease in a managed care environment, Suggested disease management guidelines.

A group of experts from gastroenterology, internal medicine, health economics, medical outcomes, and managed care met in San Francisco, Calif, on September 27, 1994, in an effort to develop clinically and economically effective disease management guidelines to assist physicians in their treatment of gastroesophageal reflux disease in a managed care environment. This article represents a consensus opinion based on the evidence and expert interpretation at the time of that meeting.

Algorithms↗

PubMed1996

orthodenticle is required for photoreceptor cell development in the Drosophila eye.

Drosophila photoreceptor cells (R cells) develop from the eye imaginal during the third instar larval stage and acquire their adult morphology during pupation. We show that orthodenticle (otd), a homeobox gene, is required for R-cell morphogenesis during pupation. otdUV-insensitive (otduvi) is a hypomorphic allele of otd that only affects R-cell development. The R-cell rhabdomeres are disorganized in otduvi, and there is a disruption of proximal-distal development in the eye. The otd genomic structure was determined and resulted in the identification of a deletion in the third intron of otduvi. Sequences encompassing this deletion are able to direct expression of the lacZ reporter gene at all stages of the developing visual system, including the photosensitive cells of Bolwig's organ, the ocelli, and the adult eye. The third intron enhancer is the primary regulatory element controlling otd in the R cells and is not under the control of the glass gene.

Alleles↗

PubMed1996

Recent corticosteroid use and the risk of complicated varicella in otherwise immunocompetent children.

OBJECTIVE: To determine whether recent corticosteroid use was associated with an increased risk of complicated varicella-zoster virus infection in otherwise immunocompetent children. STUDY DESIGN: A case-control study design was used because the outcome of interest, complicated varicella-zoster virus infection, is rare. SETTING: Cases and controls were selected from the population of children aged 2 months to 18 years admitted to two hospitals, between January 1979 and July 1994 in one and between January 1974 and July 1994 in the other, with diagnosis codes that indicated chickenpox. POPULATION: Cases were defined as children with invasive varicella-zoster virus infection or associated invasive bacterial infection. Controls were defined as children with uncomplicated varicella admitted for elective surgery, fracture or burn management, psychiatric or social evaluation, treatment of simple dehydration, or evaluation of fever or rash not yet diagnosed. Exclusions included varicella-zoster virus infection in neonates and immunocompromised children. METHODS: A priori criteria were formulated on the basis of a comprehensive literature review to define complicated varicella-zoster virus infection. Recent corticosteroid exposure was defined as corticosteroid use of any sort within 30 days of onset of the chickenpox rash. Data were abstracted by medical chart review. RESULTS: In total, 167 cases and 134 controls were identified. Only three children (two cases and one control) had a history of recent corticosteroid therapy. Recent corticosteroid exposure was therefore not statistically associated with an increased risk of complicated varicella-zoster virus infection (odds ratio, 1.6; 95% confidence interval, 0.2 to 16.9). No differences between cases and controls were found in sex, history of asthma, or length of hospital stay. The mean age of cases was greater than that of controls (6.0 vs 4.7 years; P<.01). CONCLUSIONS: Recent corticosteroid therapy in otherwise immunocompetent children does not appear to be associated with a statistically increased risk of complicated varicella. A conservative estimate of risk, using the upper limit of the 95% confidence interval, is markedly lower than previously published risk estimates.

Adolescent↗

PubMed1996

The abdominal subcutaneous tissue: computed tomographic, magnetic resonance, and anatomical observations.

We have studied the fasciae of the abdominal subcutaneous layer by analyzing axial CT images taken at a level immediately superior to the iliac crests in 20 adult female patients. The pattern of the fascial planes seen at this level was compared with those seen on MRI and dissected cadaveric sections. We have demonstrated a circumferential subcutaneous fascial plane that divides the subcutaneous fat into a single superficial fat compartment and a single deep fat compartment.

Abdominal Muscles↗

PubMed1996

[Long-term effects of nutrition with fat-reduced foods on energy consumption and body weight].

UNLABELLED: In a 3-month intervention study 70 women (40 < age < 60; 24 < BMI < 29), randomized into two groups, were supplied ad libitum and free of charge with 1) customary fat-reduced foods (D group) or 2) products with normal fat content (K group). After 6 months without any contact to the volunteers food intake and body weight were controlled. RESULTS: During the intervention period fat intake (by 22 g/d) and total energy intake (by 266 kcal/d) of the volunteers in the D group were significantly lower than in the K group. Fat reduction was not accompanied by a compensative increase in the intake of other nutrients. The weight loss was significant in the D group (1.5 kg) and not significant in the K group (0.7 kg). Between the two groups the difference in weight reduction was not significant. In the follow-up a lowered fat and energy intake had been voluntarily retained in the D group and adopted by most of the individuals in the K group. CONCLUSION: The consumption of low-fat products lowers the energy and fat intake and may be useful for a long-term weight control and health support.

Adult↗

PubMed1996

Three dimensional ultrasound: display modalities in the fetal spine and thorax.

PURPOSE: To evaluate the display modalities of three dimensional ultrasound (3D US) in the prenatal assessment of the fetal spine and thorax. METHOD: Twenty prenatal spine examinations (mean gestational age: 21 weeks, 15 normal findings, five pathological cases) were performed with a commercially available 3D US device. The visualization of fetal spine and rib anatomy and pathology by 3D US display was evaluated using various rendering methods and the optimal method was determined in regard to comprehensive diagnostic display. RESULTS: Demonstration of continuity of both the spine and the ribs could be achieved by 3D US. Visualization of clavicles, scapula and iliac bone was possible on rendered images. CONCLUSION: 3D US offers an additional diagnostic tool for prenatal assessment of the fetal spine and ribs; it provides a continuous demonstration of curved or tortuous structures in the rendered image. It improves comprehension of complex anatomy by providing a simultaneous display of all orthogonal sectional planes.

Female↗

PubMed1996

Cumulative reduction in serum cholinesterase following repeated therapeutic plasma exchange.

STUDY OBJECTIVE: To investigate the magnitude of serum cholinesterase reduction following repeated therapeutic plasma exchange in patients with neuromuscular disease. DESIGN: Serum cholinesterase activity was measured immediately before and after each plasma exchange in open-label fashion and then analyzed using an analysis of variance model. SETTING: Inpatient neurology and allergy and immunology clinics at a university-affiliated hospital. PATIENTS: 50 consecutive patients with neuromuscular disease. INTERVENTIONS: All patients underwent repeated therapeutic plasma exchange, with each subject receiving up to a maximum of six plasma exchanges. MEASUREMENTS AND MAIN RESULTS: Serum cholinesterase activity was determined spectrophotometrically. Analysis of variance revealed a significant reduction in serum cholinesterase following each therapeutic plasma exchange (p < 0.0001), a significant and consistent reduction across the six treatments (p < 0.0001), and a significant interaction between (before versus after exchange) and treatment number (p < 0.0001). Mean serum cholinesterase before repeated therapeutic plasma exchange was 4817 U/L, but it decreased to a mean of 929 U/L following six plasma exchanges. CONCLUSIONS: There is a significant reduction in serum cholinesterase following repeated therapeutic plasma exchange. It is suggested that drugs metabolized by serum cholinesterase (e.g., succinylcholine, mivacurium) be used with caution in the period immediately following repeated therapeutic plasma exchange.

Anesthesia↗

PubMed1996

Unusual features of osteoarticular tuberculosis in children.

Three children with tuberculous arthritis, two of whom also had tuberculous otitis media, are described. Two of the children were atypical at presentation, with an acute onset of arthritis, an elevated erythrocyte sedimentation rate, and a predominance of polymorphonuclear cells in the joint fluid. Both had histories of recurrent otitis media with perforations. Recognition that Mycobacterium tuberculosis could be the cause of disease in all three cases was delayed. Placement of a tuberculin skin test ultimately led to the correct diagnosis. These cases Illustrate that tuberculous arthritis is not always insidious in onset and underscore the need to maintain a high index of suspicion for tuberculosis infection in high-risk patient populations. Our experiences suggest that Mantoux skin tests might be considered part of the "routine" diagnostic study of children with arthritis or recurrent otitis media, especially in communities with high tuberculosis case rates.

Adolescent↗

PubMed1996

Anisometropia and binocularity.

PURPOSE: To determine the effects of experimentally induced anisometropia on binocular function in healthy adults as a means of assessing the potentially detrimental effects of uncorrected anisometropia on binocular development in childhood. METHODS: Nineteen adults with normal binocularity, ranging in age from 26 to 59 years, were studied. Unilateral myopia, hyperopia, or astigmatism (at 90 degrees or 45 degrees) was induced in each subject using trial lenses. Sensory status then was assessed by measuring stereoacuity, Worth four-dot fusion, and Bagolini lens response. RESULTS: All subjects showed a decline in binocular function with increasing levels of anisometropia. Foveal suppression was evident on the Worth four-dot test, and increased in proportion to the anisometropia. Stereoacuity was similarly degraded by the induced anisometropia, with some subjects showing significant loss of stereoacuity with as little as 1 diopter of spherical anisometropia. Bagolini lens responses were binocular in almost all patients, although occasional abnormalities were found. CONCLUSIONS: Relatively low degrees of anisometropia may cause significant abnormalities in high-grade binocular visual functions in adults. The potential effects of uncorrected anisometropia on binocularity in children require further investigation, but should be considered in developing guidelines for the empiric correction of refractive errors.

Adult↗

PubMed1996

Augmentation of hypoxic pulmonary vasoconstriction by N(G)-L-methyl-arginine in a rabbit model of thermal injury.

We tested deeply anesthetized rabbits to determine if a burn acutely diminished the strength of hypoxic pulmonary vasoconstriction (HPV) and if this could be augmented by L-NMMA, a nitric oxide synthase inhibitor. We induced a burn using water heated to 75 degrees C and assessed the strength of HPV as the difference in pulmonary vascular resistance during 100% and 13% O2 ventilation. The rabbits then were randomized to receive 10 mg/kg L-NMMA (n = 8) or a placebo (n = 8). The strength of HPV decreased from 0.42 +/- 0.11 mm Hg/mL/min preburn to 0.22 +/- 0.11 mm Hg/mL/min postburn (P <.05). L-NMMA administration augmented HPV to a postburn value of 0.48 +/- 0.014 mm Hg/mL/min (P <.05). We speculate that the loss of HPV following a burn could worsen ventilation to perfusion mismatch and thereby aggravate the hypoxia associated with burns. Augmentation of HPV might be a short-term goal during the acute stabilization of hypoxic burn patients.

Animals↗

PubMed1996

Anti-CD18 antibodies improve cardiac function following cardiopulmonary bypass in dogs.

PURPOSE: Cardiopulmonary bypass is associated with activation of neutrophils, which may adhere to vascular endothelium causing lung, heart, and brain injury. We tested whether blocking neutrophil adherence would improve organ function following cardiopulmonary bypass in dogs. MATERIALS AND METHODS: All dogs received a standard anesthetic, and then one group (n = 6) received 2 hours of cardiopulmonary bypass followed by 4 hours of observation. A second group (n = 6) received a monoclonal antibody (6 mg/kg) to CD18, a neutrophil adherence factor, immediately before cardiopulmonary bypass. A third group (n = 6) did not receive cardiopulmonary bypass or antibody. RESULTS: Using flow cytometry we found that the antibody bound essentially all neutrophil CD18 sites. All three groups had similar gas exchange and hemodynamics. Lung and heart histology results were similar between groups. By echocardiography, five animals receiving cardiopulmonary bypass alone showed regional wall abnormalities, whereas only one receiving antibody showed wall motion abnormality (P < .05). Following cardiopulmonary bypass, intracellular myocardial pH was higher (P < .05) in the antibody-treated group compared with the group that had cardiopulmonary bypass alone (7.23 +/- 0.05 v 7.07 +/- 0.07 respectively). CONCLUSION: Monoclonal antibodies to CD18 can prevent the deterioration in cardiac function routinely observed following cardiopulmonary bypass.

Analysis of Variance↗

PubMed1996

Luminal proteinases from Plodia interpunctella and the hydrolysis of Bacillus thuringiensis CryIA(c) protoxin.

The ability of proteinases in gut extracts of the Indianmeal moth, Plodia interpunctella, to hydrolyze Bacillus thuringiensis (Bt) protoxin, casein, and rho-nitroanilide substrates was investigated. A polyclonal antiserum to protoxin CryIA(c) was used in Western blots to demonstrate slower protoxin processing by gut enzymes from Bt subspecies entomocidus-resistant larvae than enzymes from susceptible or kurstaki-resistant strains. Enzymes from all three strains hydrolyzed N-alpha-benzoyl-L-arginine rho-nitroanilide, N-succinyl-ala-ala-pro-phenylalanine rho-nitroanilide, and N-succinyl-ala-ala-pro-leucine rho-nitroanilide. Zymograms and activity blots were used to estimate the apparent molecular masses, number of enzymes, and relative activities in each strain. Several serine proteinase inhibitors reduced gut enzyme activities, with two soybean trypsin inhibitors, two potato inhibitors, and chymostatin the most effective in preventing protoxin hydrolysis.

Animals↗

PubMed1996

Respiratory function after cardiac surgery.

STUDY OBJECTIVE: Cardiac surgery is complicated by decreased postoperative respiratory muscle strength and spirometry with accompanying increased atelectasis. The specific respiratory symptoms attributable to these physiologic changes are unknown, and this study looked at the symptoms and underlying physiology. DESIGN: Convenience sampling of observational cohort. SETTING: Tertiary care university hospital. PATIENTS: One hundred thirty-eight patients undergoing elective surgery were enrolled. INTERVENTIONS: Changes from admission to 8-week postoperative values in atelectasis, pleural effusions, spirometry (forced vital capacity and forced expiratory volume in one second), and respiratory muscle strength (negative inspiratory pressure) were measured. These physiologic changes were compared with changes in respiratory symptoms of cough, wheeze, phlegm, and dyspnea on walking up a slight hill noted from admission to 8-week follow-up by stepward logistic regression. MEASUREMENTS AND RESULTS: Spirometry and negative inspiratory pressure decreased and atelectasis increased from admission to discharge. These disturbances had only incompletely resolved at 8-week follow-up. Some patients reported fewer symptoms of cough (11%), phlegm (9%), wheeze (35%), and dyspnea (46%) at 8 weeks follow-up. Other patients reported increased symptoms of cough (15%), phlegm (10%), wheeze (6%), and dyspnea (4%) at 8 weeks follow-up. Residual atelectasis at 8 weeks was predictive of fewer symptoms of dyspnea (odds ratio [OR] 0.335, p = 0.199; 95% confidence interval [CI] 0.188, 0.597), increased symptoms of dyspnea (OR 855, p = 0.006; 95% CI 6.6, 11052), and increased symptoms of cough (OR 260, p = 0.023; 95% CI 2.13, 31829). Negative inspiratory pressure at 8 weeks was predictive of fewer symptoms of dyspnea (OR 1.05, p = 0.032; 95% CI 1.02, 1.09) and increased symptoms of wheeze (OR 0.7, p = 0.45; 95% CI 0.533, 0999). Forced vital capacity at 8 weeks was predictive of increased symptoms of wheeze (OR 0.005; p = 0.015; 95% CI 0.0060, 0.775). CONCLUSIONS: Postoperative changes in respiratory muscle strength and spirometry can persist up to at least 8 weeks postoperatively. Many patients report a change in respiratory symptoms of cough, phlegm, dyspnea, or wheeze. The change in respiratory symptoms at 8 weeks is correlated with residual respiratory muscle weakness, decrease in spirometry, and residual atelectasis.

Adult↗