Readers' responses to "where is physician leadership on reform?".
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Health Care Reform↗
Biomedical subjects
S L Williams
Publications and source records attributed to S L Williams.
Ecology. Aquaculture--a gateway for exotic species.
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Animals↗
A novel mutation in SURF1 causes skipping of exon 8 in a patient with cytochrome c oxidase-deficient leigh syndrome and hypertrichosis.
Leigh syndrome is a rare pediatric neurodegenerative disorder attributed to impaired mitochondrial energy metabolism. Mutations in SURF1 have been described in several patients with Leigh syndrome associated with cytochrome c oxidase deficiency. We report a new 18-bp deletion (821del18), spanning the splice donor junction of exon 8 of SURF1, in an infant presenting with cytochrome c oxidase-deficient Leigh syndrome and hypertrichosis. cDNA sequencing demonstrated that this deletion results in a messenger lacking exon 8. RT-PCR experiments suggested a rapid degradation of the aberrant mRNA species from the 5'-end.
Alternative Splicing↗
Immunological phenotyping of fibroblast cultures from patients with a mitochondrial respiratory chain deficit.
Conventional approaches to the diagnosis of mitochondrial respiratory chain diseases, using enzyme assays and histochemistry, are laborious and give limited information concerning the genetic basis of a deficiency. We have evaluated the diagnostic value of 12 monoclonal antibodies to subunits of the four respiratory chain enzyme complexes and F(1)F(0)-ATP synthase. Antibodies were used in immunological studies with skin fibroblast cultures derived from patients with diverse mitochondrial diseases, including patients in which the disease was caused by a nuclear genetic defect and patients known to harbor a heteroplasmic mutation in a mitochondrial tRNA gene. Immunoblotting experiments permitted the identification of specific enzyme assembly deficits and immunocytochemical studies provided clues regarding the genetic origin of the disease. The immunological findings were in agreement with the biochemical and genetic data of the patients. Our study demonstrates that characterization of the fibroblast cultures with the monoclonal antibodies provides a convenient technique to complement biochemical assays and histochemistry in the diagnosis of mitochondrial respiratory chain disorders.
Adult↗
Assembly of cytochrome c oxidase: what can we learn from patients with cytochrome c oxidase deficiency?
Cytochrome c oxidase is an intricate metalloprotein that transfers electrons from cytochrome c to oxygen in the last step of the mitochondrial respiratory chain. It uses the free energy of this reaction to sustain a transmembrane electrochemical gradient of protons. Site-directed mutagenesis studies of bacterial terminal oxidases and the recent availability of refined crystal structures of the enzyme are rapidly expanding the understanding of the coupling mechanism between electron transfer and proton translocation. In contrast, relatively little is known about the assembly pathway of cytochrome c oxidase. Studies in yeast have indicated that assembly is dependent on numerous proteins in addition to the structural subunits and prosthetic groups. Human homologues of a number of these assembly factors have been identified and some are now known to be involved in disease. To dissect the assembly pathway of cytochrome c oxidase, we are characterizing tissues and cell cultures derived from patients with genetically defined cytochrome c oxidase deficiency, using biochemical, biophysical and immunological techniques. These studies have allowed us to identify some of the steps of the assembly process.
Animals↗
Methylene blue based protein solder for vascular anastomoses: an in vitro burst pressure study.
BACKGROUND AND OBJECTIVE: Attempts at sutureless anastomoses have used protein-based solders containing chromophores [Oz et al., J Vasc Surg 1990;11:718; Poppas et al., J Urol 1998150:1052] to enhance the strength of laser anastomoses. Reports have described the use of indocyanine green [Oz et al., Surg Forum 1989;316.], fuschin, and fluorescein isothiocyanate as chromophores [Chuck et al. , Lasers Surg Med 1989;9:471; Vance et al., Lasers Med Sci 1988;3:219]. Methylene blue (MB) is a chromophore with absorption peaks in the 600-700 nm region whose use has not been reported in laser-assisted vascular anastomoses. Therefore, we set out to produce and characterise a MB-containing protein solder. The absorption and burst pressure characteristics have been investigated and described as well as a brief review of the chemical and biological properties of MB. STUDY DESIGN/MATERIALS AND METHODS: The MB and porcine serum albumin (PSA)-based solder was produced and used to form end-to-end anastomoses in porcine splenic arteries. The solder was activated using a laser diode emitting at 670 nm. The burst pressures of the anastomoses were tested, and the results analysed as a function of MB concentration and absorption. In addition, the relationship between MB concentration and absorption was examined. RESULTS: A dose-response relationship was found between the measured absorption of the solder and the burst pressure of the anastomoses formed. Burst pressures exceeding physiological levels were found. Changes in MB concentration revealed a marked negative deviation from Beer's law at 670 nm, owing to the monomer-dimer-trimer equilibria. CONCLUSION: PSA with MB solder is able to form high-quality end-to-end anastomoses, with immediate burst pressure profiles similar to those previously described for sutured [Quigley et al., Microsurgery 1985;6:229], lasered [Quigley et al., Microsurgery 1985;6:229], and soldered anastomoses [Small et al., J Clin Laser Med Surg 1997;15:205]. The relationship between burst pressure strength and chromophore absorption is discussed.
Absorption↗
Development of a firefly luciferase-based assay for determining antimicrobial susceptibility of Mycobacterium avium subsp. paratuberculosis.
Paratuberculosis (Johne's disease) is a fatal disease of ruminants for which no effective treatment is available. Presently, no drugs against Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis), the causative agent of Johne's disease, are approved for use in livestock. Additionally, M. paratuberculosis has been linked to a human chronic granulomatous ileitis (Crohn's disease). To assist in the evaluation of antimicrobial agents with potential activity against M. paratuberculosis, we have developed a firefly luciferase-based assay for the determination of drug susceptibilities. The microorganism used was M. paratuberculosis K-10(pYUB180), a clinical isolate carrying a plasmid with the firefly luciferase gene. The MICs determined by the broth macrodilution method were as follows: amikacin, 2 microg/ml; Bay y 3118, 0.015 microg/ml; clarithromycin, 1.25 microg/ml; D-cycloserine, 25 microg/ml; ethambutol, 20 microg/ml; and rifabutin, 0.5 microg/ml. The strain was resistant to isoniazid and kanamycin. The results obtained by the luciferase assay were identical or fell within 1 doubling dilution. These results suggest that a combination of amikacin, clarithromycin, and rifabutin may be the most efficacious therapy for the treatment of M. paratuberculosis infections and that the use of fluoroquinolone class of antibiotics deserves further consideration. We demonstrate that the luciferase drug susceptibility assay is reliable for M. paratuberculosis and gives results within 7 days, whereas the broth macrodilution method requires 14 days.
Anti-Bacterial Agents↗
Vocal expression of anger and cardiovascular reactivity within dyadic interactions.
This experiment was conducted to examine whether the vocal expression of anger correlated with cardiovascular reactivity within dyadic interactions. Participants selected three social issues on which they had a strong opinion and, with a confederate who opposed their views, debated these opinions in each of the three vocal styles. The three vocal styles were (1) Anger-out during which they described their view in a loud, fast voice, (2) Mood-incongruent during which they described their view in a soft, slow voice, and (3) Anger-in during which they listened to the confederate oppose their view and only responded from a list of neutral phrases given to them. Cardiovascular reactivity measures (heart rate and blood pressure) were taken during the initial baseline and the three expression of anger conditions. Both the anger-out and mood-incongruent vocal styles significantly correlated with systolic blood pressure and heart-rate reactivity measures. The disparity between the results of this experiment and previous ones on anger and cardiovascular response may be related to differences in the method of anger-arousal (memory-evoked versus dyadic interactions). Results are discussed in terms of similarities to active and passive coping and defensiveness.
Adult↗
An independent evaluation of the Age-Related Eye Disease Study (AREDS) cataract grading system.
PURPOSE: To assess intra- and interobserver reproducibility of the Age-Related Eye Disease Study (AREDS) system for grading lens opacities and to provide data on its capacity to reliably detect changes in lens status. METHODS: Independent and replicate grading of 40 sets of lens photographs (one slit-lamp and two retroillumination photographs) were performed by three experienced observers. Patients were participants in the Collaborative Italian-American Clinical Trial of Nutritional Supplements which is testing the effect of a mineral-multivitamin supplement on age-related cataract (CTNS). Scatterplots and intraclass correlation were used to assess measurement error. RESULTS: Analysis revealed good intra- and interobserver reproducibility of the system. Greatest intraobserver measurement error showed 100% of pairs within 10% areal difference for cortical cataract, 97.5% within 15% areal difference for posterior subcapsular cataract, and 100% within 1 density unit difference for nuclear opacity. Greatest interobserver measurement error showed 95% of pairs within 10% areal difference for cortical cataract, 97.5% within 15% areal difference for posterior subcapsular cataract, and 97.5% within 1.5 density unit difference for nuclear opacity. CONCLUSIONS: The AREDS lens opacities grading system appears to be sufficiently reliable to detect changes of at least 10% areal involvement for cortical, 15% areal involvement for posterior subcapsular, and 1.0 units for nuclear opacities. It therefore seems sufficiently sensitive to adequately monitor progression of lens opacities in a longitudinal study of patients with early cataract. Its applicability in a population with advanced or complex mixed opacities must await further testing.
Aging↗
The activity of rifabutin against Mycobacterium leprae in armadillos.
The activity of rifabutin (LM 427) against Mycobacterium leprae was evaluated in armadillos inoculated earlier with human-derived M. leprae. Rifabutin was administered daily at a dose of 6 mg/kg body weight/day. The effect of rifabutin on M. leprae harvested from armadillos was determined by measuring the intracellular levels of ATP (an indicator of metabolic activity) of M. leprae and also their ability to multiply in the mouse footpads and in vitro in DH medium. Within 2 weeks of initiating the treatment, ATP levels declined to 21% of the original (pre-treatment level) and these M. leprae failed to multiply in the footpads of mice as well as in the in vitro culture system. This suggests that rifabutin was able to kill all M. leprae within 2 weeks. After 8 weeks the treatment was terminated and results showed that M. leprae from the treated armadillos remained non-viable in the mouse footpad system as well as in the in vitro system, indicating bactericidal action of rifabutin. The results suggest that rifabutin can be a substitute for rifampin in the leprosy multi-drug therapy regimen.
Animals↗
Thoughts of agoraphobic people during scary tasks.
The authors examined the occurrence of theoretically derived patterns of thinking in 74 agoraphobic participants as they drove alone or tolerated an enclosed place. During the increasingly scary tasks in a behavioral test hierarchy, participants responded to a periodic beep by stating aloud what they were thinking at that moment, yielding more than 1,800 tape-recorded statements. Content analyses revealed that participants were mainly preoccupied with their current anxiety (expressed in 29% of the statements) and with their self-efficacy (15%). Despite participants' mounting feelings of anxiety, fewer than 1% of their statements expressed a thought of danger or an anticipation of future anxiety or panic. The rarity of danger thoughts poses an explanatory challenge for all cognitive theories of phobia and especially for the perceived danger theory of A. T. Beck (1976) and A. T. Beck, G. Emery, and R. L. Greenberg (1985).
Adult↗
The effects of human macrophage inflammatory protein-1 alpha and its genetically modified variant, BB10010, on phagocyte function.
BB-10010 is a genetically modified form of human macrophage inflammatory protein-1 alpha (MIP-1 alpha) with a single amino acid substitution of Asp26 by alanine, which inhibits aggregation of the native molecule. BB-10010 has stem cell protective properties, and has entered clinical trials for this purpose. The aim of this study was to determine the effects of BB-10010 on human phagocyte function and compare them with the native molecule. MIP-1 alpha and BB-10010 had identical dose-response curves in assays of calcium mobilization; however, neutrophils were less sensitive than monocytes to either MIP-1 alpha form, suggesting differences in receptor expression. Neither MIP-1 alpha type directly stimulated phagocyte superoxide production, nor did it have any priming effect on agonist-induced superoxide production. Both MIP-1 alpha and BB-10010 enhanced monocyte migration; however, cells were more sensitive to the native molecule, with optimal effects seen at 1 ng/ml compared with 100 ng/ml BB-10010. Concomitant alteration of CD11b, CD18, and CD49d (VLA-alpha 4) cell adhesion molecule expression was not seen with either MIP-1 alpha type. With the exception of the difference in monocyte sensitivity in chemotaxis assays, BB-10010 reproduces the effects of the native molecule on phagocytes. BB-10010 does not have proinflammatory effects on neutrophil activation, and this bodes well for its clinical use.
Calcium↗
A functional model of nerve repair. Reanastomosis vs entubulation repair.
OBJECTIVE: To compare reanastomosis and entubulation repair after transection of the peroneal nerve in rats with the use of 2 functional models: gait analysis and a tension transduction device. DESIGN: Prospective, randomized, blinded control study. Each animal served as its own control. The injured site was alternated between the left and the right. Gait analysis was evaluated in a blind fashion at postoperative weeks 1, 3, 7, and 13, and the tension transduction device at week 13, for injured and uninjured legs. SUBJECTS: Animals underwent unilateral peroneal nerve transection injury, half with entubulation and half with end-to-end reanastomosis repair. INTERVENTION: Nerve transection was performed 6 mm proximal to the anterior tibialis muscle insertion followed by reanastomosis (epineurial suture placement to align the sectioned nerve ends) or entubulation (placement of nerve ends into a 4-mm-long sterile Silastic tube secured with 2 epineurial sutures). RESULTS: Gait analysis demonstrated a poorer ankle angle in all injured legs compared with uninjured legs at each postoperative period. Ankle angles for reanastomosis were statistically better than those for entubulation at weeks 3, 7, and 13. The tension transduction device demonstrated poorer force in injured than uninjured animals at 13 weeks. Reanastomosis repair groups demonstrated no difference in force development compared with entubulation repair groups. CONCLUSIONS: Reanastomosis of the transected rat peroneal nerve demonstrated improved functional return by gait analysis when compared with entubulation-repaired nerves at postoperative weeks 3, 7, and 13. Force development of injured nerve groups measured by the tension transduction device was decreased compared with control, but no difference was detected between the 2 repair methods. Further studies are needed to evaluate the possible functional benefit of reanastomosis.
Anastomosis, Surgical↗
A quantitative cytological study of lesional and non-lesional mucosa in oral lichen planus.
Smears of buccal mucosa, dorsal surface of the tongue and floor of mouth were taken from 10 patients with histologically confirmed oral lichen planus and 12 healthy age- and sex-matched controls. In buccal smears, no significant differences in cytoplasmic and nuclear areas were observed between lesional, adjacent non-lesional and control tissues. However, the cytoplasmic area in smears from lichen planus lesions on the dorsum of the tongue and adjacent clinically normal mucosa was reduced compared with healthy controls. The cytoplasmic: nuclear ratio in smears from clinically normal floor of mouth in oral lichen planus was similarly reduced. Papanicolaou-stained smears from buccal lichen planus showed increased keratinization compared with normal buccal mucosa. These findings demonstrate that quantitative cytology can detect both cytoplasmic and nuclear changes in oral lichen planus.
Adult↗
Cognitive and performance-based treatments for panic attacks in people with varying degrees of agoraphobic disability.
Compared the effectiveness of cognitive therapy and performance-based exposure as treatments for panic attacks. Subjects were 48 panicky individuals selected without regard to agoraphobic disability, and who varied widely in that respect. Subjects were assigned randomly to either cognitive treatment, performance-based exposure treatment, a combined cognitive/performance treatment, or a no-treatment control condition. All three treatments led to marked and enduring improvements in panic, and did not differ from one another in effectiveness, whereas the control condition produced little benefit. However, on several measures of phobia and panic-related cognitions, performance exposure was significantly more effective than cognitive therapy. Degree of agoraphobic disability had a significant bearing on panic treatment effectiveness. Whereas 94% of the low agoraphobia Ss were free of panic after treatment, only 52% of the high agoraphobia Ss became panic-free. The findings suggest that when panic treatment research excludes people with serious phobias, as it has routinely done in recent years, an overly positive estimate of panic treatment effectiveness can result.
Adolescent↗
Hyperbaric oxygen treatment after rat peroneal nerve transection and entubulation.
Rat peroneal nerves were transected and entubulated with a Silastic channel. The experimental group was treated with hyperbaric oxygen to evaluate changes in acute edema, functional recovery, and histology. Hyperbaric oxygen was administered with 100% O2 at 2.5 atmospheres absolute for 90 minutes twice a day for 1 week and then four times a day for 1 week. Acute edema changes based on nerve water weight and transfascicular area measurements were greater in injured than in uninjured nerves but demonstrated no differences between hyperbaric oxygen-treated and -untreated groups 2, 8 and 16 days after surgery. Functional evaluation with gait analysis demonstrated significant changes between injured and uninjured group 1, 3, 7, and 13 weeks after injury but no differences between hyperbaric oxygen-treated and -untreated groups. Thirteen weeks after the initial injury, elicited muscle force measurements demonstrated no significant improvement from hyperbaric oxygen treatment of injured nerves. Histologic evaluation of nerve area, myelinated axon number, myelinated axon area, myelin thickness, and blood vessel number and area revealed no significant differences between hyperbaric oxygen-treated and -untreated groups. Hyperbaric oxygen was not associated with improvement of nerve regeneration with any of the outcome variables in this model.
Animals↗
The regulation of neutrophil phospholipase A2 by granulocyte-macrophage colony-stimulating factor and its role in priming superoxide production.
Experiments were performed to investigate the relative role of phospholipase A2 (PLA2) in the activation and cytokine-mediated priming of neutrophil superoxide production. PLA2 activity was measured with a radiometric assay which discriminates between PLA2 and the downstream enzyme, 5-lipoxygenase. In cells that had not been primed by prior incubation with granulocyte-macrophage colony stimulating factor (GM-CSF), PLA2 and NADPH oxidase were differentially stimulated by the chemotactic peptide N-formyl-met-leu-phe (FMLP), calcium ionophore, or phorbol ester. In addition, inhibition of PLA2 by mepacrine (0-100 micromol/l) did not concomitantly inhibit FMLP-stimulated superoxide production. These findings suggest that the activity of PLA2 and NADPH oxidase may be uncoupled in the unprimed cell. In cells preincubated with GM-CSF, time- and dose-dependent priming of FMLP-stimulated PLA2 responses were observed and inhibition of PLA2 by mepacrine was accompanied by the inhibition of FMLP-stimulated superoxide production down to the level of unprimed cells. The effect of mepacrine was not due to inhibition of FMLP receptor expression. These data suggest that a mepacrine-sensitive PLA2 may have a role in the GM-CSF mediated priming of superoxide production. Using ionophore-stimulated PLA2 activity as a model, we showed that Bordatella pertussis toxin did not inhibit GM-CSF mediated priming, demonstrating that a pertussis-sensitive GTP-binding protein does not mediate signal transduction from the GM-CSF receptor to PLA2. The tyrosin kinase inhibitor, genestein, selectively inhibited GM-CSF primed but not unprimed PLA2 activity, demonstrating that GM-CSF-mediated priming requires tyrosine kinase activity.
Arachidonic Acid↗
Peroneal motor nerve crush injury and hyperbaric oxygen effect.
The potential therapeutic effect of hyperbaric oxygen (HBO) after rat peroneal nerve crush was evaluated. Animals were given 100% oxygen at 2.5 atmosphere absolute for 90 minutes twice daily for 1 week and then once daily for 1 week. Edema increased in crushed nerves compared with control nerves, but no effect was associated with the administration of HBO. Gait analysis demonstrated injury at 1, 7, and 14 days after nerve crush, but no difference was found at 22 and 28 days after injury (analysis of variance: P < .001, 10 animals per group). Eight weeks after injury, nerve stimulation and muscle force measurements were 114 g for the injured group and 146 g for the control group (P < .001). There were no HBO-associated changes in gait parameter or nerve/muscle force measurements. This study demonstrated that rat peroneal nerve crush injury causes acute intraneural edema and temporary decrement of gait parameters. Elicited nerve stimulation demonstrated persistent loss of force 4 weeks after normalization of gait, but no HBO effect.
Acute Disease↗