Disseminated Pseudallescheria boydii infection successfully treated with voriconazole.
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Antifungal Agents↗
Biomedical subjects
E K Johnson
Publications and source records attributed to E K Johnson.
Vocational rehabilitation in multiple sclerosis (MS): a profile of clients seeking services.
Although a number of innovative vocational rehabilitation (VR) demonstration projects have been completed with MS populations, there remains a lack of clarity as to a profile of these VR participants. An effort is made in this article to carefully describe the demographic and occupational characteristics of people with MS seeking vocational services at intake, as well as their self-perceived psychosocial functioning across a range of pertinent measures. The issue of "program dropouts" in VR services for people with MS is also addressed. Implications for better understanding participants with MS within the VR process and improved nuances in service delivery are then discussed.
Adult↗
Statistical learning of tone sequences by human infants and adults.
Previous research suggests that language learners can detect and use the statistical properties of syllable sequences to discover words in continuous speech (e.g. Aslin, R.N., Saffran, J.R., Newport, E.L., 1998. Computation of conditional probability statistics by 8-month-old infants. Psychological Science 9, 321-324; Saffran, J.R., Aslin, R.N., Newport, E.L., 1996. Statistical learning by 8-month-old infants. Science 274, 1926-1928; Saffran, J., R., Newport, E.L., Aslin, R.N., (1996). Word segmentation: the role of distributional cues. Journal of Memory and Language 35, 606-621; Saffran, J.R., Newport, E.L., Aslin, R.N., Tunick, R.A., Barrueco, S., 1997. Incidental language learning: Listening (and learning) out of the corner of your ear. Psychological Science 8, 101-195). In the present research, we asked whether this statistical learning ability is uniquely tied to linguistic materials. Subjects were exposed to continuous non-linguistic auditory sequences whose elements were organized into 'tone words'. As in our previous studies, statistical information was the only word boundary cue available to learners. Both adults and 8-month-old infants succeeded at segmenting the tone stream, with performance indistinguishable from that obtained with syllable streams. These results suggest that a learning mechanism previously shown to be involved in word segmentation can also be used to segment sequences of non-linguistic stimuli.
Adult↗
The slump test: the effects of head and lower extremity position on knee extension.
Maitland's slump test is a widely used neural tissue tension test. During slump testing, terminal knee extension is assessed for signs of restricted range of motion (ROM), which may indicate impaired neural tissue mobility. A number of refinements that modify hip and ankle position has been added to the basic slump test procedure, but no research to date has measured the effects of ankle and hip position on knee extension ROM during testing. The purpose of this study was to examine the effect of neural tension-producing movements of the cervical spine and lower extremity on knee extension ROM during the slump test. Thirty-four males with no significant history of low back pain were tested in the slump position with the cervical spine flexed and extended in each of three lower extremity test positions: neutral hip rotation with the ankle in a position of subject comfort (neutral), neutral hip rotation with ankle dorsiflexion (ankle dorsiflexion), and medial hip rotation with ankle dorsiflexion. Results showed significant decreases in active knee extension ROM (F1,198 = 29.53, p < 0.0001) in the cervical flexion compared with the cervical extension conditions. Subjects also exhibited significant decreases in active knee extension ROM (F2,198 = 56.76, p < 0.0001) as they were progressed from neutral to the ankle dorsiflexion to the medial hip rotation with ankle dorsiflexion positions of the lower extremity. The results of our study indicate that limitations in terminal knee extension ROM may be considered a normal response to the inclusion of cervical flexion, ankle dorsiflexion, or medial hip rotation in the slump test in young, healthy, adult males. In addition, the presence of a cumulative effect on knee extension ROM with the simultaneous application of these motions is noted. These findings may assist clinicians when assessing knee extension ROM during slump testing.
Adult↗
The role of extracellular ions in the pathogenesis of myonecrosis induced by a myotoxin isolated from Broad-Banded copperhead (Agkistrodon contortrix laticinctus) venom.
Pathological changes in murine skeletal muscle cells induced by ACL (Agkistrodon contortrix laticinctus, Broad-Banded Copperhead) myotoxin in vivo were compared to pathological changes induced by an influx of Ca2+ and other ions into cut skeletal muscle cells in vitro in the absence of myotoxin. In vivo, ACL myotoxin induced a rapid myonecrosis characterized by densely clumped myofibrils in the cytoplasm. In vitro, this pathological change was not produced by incubating skeletal muscle cells in Ca2+ concentrations as high as 200 mM, whereas skeletal muscle cells incubated in concentrations of 150 mM and 300 mM NaCl contained densely clumped myofibrils similar in morphology to muscle cells damaged by ACL myotoxin in vivo. Treatments of 300 mM KCl did not produce densely clumped myofibrils in muscle cells. These results suggest that an influx of Na+, possibly through disrupted regions of sarcolemma, may be primarily responsible for the pathological changes, including clumped myofibrils, induced by ACL myotoxin in vivo. However, an influx of extracellular Ca2+ which has been proposed to produce densely clumped myofibrils in muscle cells damaged by other snake venom myotoxins, may not be responsible for this pathological change since extracellular Ca2+ concentrations much higher than physiological levels did not produce this change in skeletal muscle cells in vitro.
Agkistrodon↗
Isolation of a hemorrhagic toxin from the venom of Agkistrodon contortrix laticinctus (broad-banded copperhead) and pathogenesis of the hemorrhage induced by the toxin in mice.
1. A hemorrhagic toxin was isolated from the venom of Agkistrodon contortrix laticinctus (Broad-Banded Copperhead) by Sephacryl S-200 HR column chromatography followed by high performance chromatography on Waters DEAE 5PW and protein Pak 125 columns. 2. Homogeneity was determined by the presence of a single band in acrylamide gel electrophoresis with silver staining. 3. ACL hemorrhagic toxin I has a molecular weight of about 29,000, is slightly acidic, and is a metalloprotease with activity towards the substrates N,N-dimethylcasein and bovine fibrinogen. Although the toxin is able to hydrolyze fibrinogen in vitro, it does not possess any defibrinogenating activity in vivo whereas the crude venom does show this activity. It has similar cleavage specificities to other snake venom hemorrhagic toxins. 4. ACL hemorrhagic toxin I causes hemorrhage of rapid onset, present within 5 min of intramuscular injection into mice, and the pathogenesis is one of hemorrhage per rhexis in which capillary endothelial cells are ruptured.
Animals↗
Isolation of a myotoxin from the venom of Agkistrodon contortrix laticinctus (broad-banded copperhead) and pathogenesis of myonecrosis induced by it in mice.
A myotoxin was isolated from the venom of the broad-banded copperhead (Agkistrodon contortrix laticinctus) by HPLC using anion and cation exchange chromatography. The toxin has a mol. wt of approximately 14,000 and has a pI greater than 9. It does not have phospholipase A activity, but does induce myonecrosis of skeletal muscle cells characterized by a hypercontraction of myofilaments. Electron microscopic analysis showed that the myotoxin appears to disrupt the sarcolemma of skeletal muscle cells. ACL myotoxin is very similar in mol. wt, amino acid composition, and myotoxic activity to myotoxins isolated from the venoms of Bothrops asper and Bothrops nummifer from Central America, suggesting that homologs of this toxin may be found in other crotaline snake venoms.
Amino Acids↗
Memory processes in children: implications for investigations of alleged child sexual abuse.
Allegations of child sexual abuse naturally raise the ire of the populace at large, as well as the fears and apprehensions of those who may be falsely accused as perpetrators. Within this emotionally charged and litigious climate, the memory functions of children have become a matter of acute interest for those professionals involved in the ensuing investigations and legal proceedings. This is especially true, given that the child witness, approaching a court of law, is likely to encounter numerous circumstances that will invite memory distortion. These circumstances include interviews by concerned adults and protective service workers, as well as cross-examination by a defense attorney. Well-intentioned efforts may be replete with leading questions or subtle inferences that may distort episodic memory. The present paper will discuss developmental aspects of long-term memory functions in children, events, and cognitive processes that may contribute to memory distortion, and recommendations for improving procedures related to the investigations of alleged child sexual abuse.
Child↗
Current practices in admission interviews at U.S. medical schools.
Although the interview is widely used in the selection of applicants for admission to U.S. medical schools, little is known about current interview practices. The authors formulated a 46-item questionnaire concerning the interview process for medical school applicants, then in 1989 sent it to admission officials at all the 127 LCME-accredited schools in the United States. The questionnaire concerned the interview's status as a predictor; interviewers and interview structure; interviewer training; and the utility of interview data. Seventy-two percent of those sent the questionnaire completed and returned it. The responding admission officials indicated that the interview had two major purposes at their schools: as a means of assessing candidates' noncognitive skills and as a public relations tool. Most schools' interview processes were loosely to moderately structured, and interviewers received minimal training. It is concluded that the interview's role is primarily subjective and that it has a definite but imprecise influence on admission decisions.
Education, Medical, Undergraduate↗
The interview in the admission process.
Significant demographic, legal, and educational developments during the last ten years have led medical schools to review critically their selection procedures. A critical component of this review is the selection interview, since it is an integral part of most admission processes; however, some question its value. Interviews serve four purposes: information gathering, decision making, verification of application data, and recruitment. The first and last of these merit special attention. The interview enables an admission committee to gather information about a candidate that would be difficult or impossible to obtain by any other means yet is readily evaluated in an interview. Given the recent decline in numbers of applicants to and interest in medical school, many schools are paying closer attention to the interview as a powerful recruiting tool. Interviews can be unstructured, semistructured, or structured. Structuring involves analyzing what makes a medical student successful, standardizing the questions for all applicants, providing sample answers for evaluating responses, and using panel interviews (several interviewers simultaneously with one applicant). Reliability and validity of results increase with the degree of structuring. Studies of interviewers show that they are often biased in terms of the rating tendencies (for instance, leniency or severity) and in terms of an applicant's sex, race, appearance, similarity to the interviewer, and contrast to other applicants). Training interviewers may reduce such bias. Admission committees should weigh the purposes of interviewing differently for various types of candidates, develop structured or semistructured interviews focusing on nonacademic criteria, and train the interviewers.
Bias↗
Electric shocks are ineffective in treatment of lethal effects of rattlesnake envenomation in mice.
Electrical shocks, even crudely delivered from 'stun guns' and gasoline engine spark plugs, have been reported to be effective in the treatment of snake bite. We thus applied similar electric shocks to mice artificially injected with reconstituted rattlesnake venom at various LD50 multiples. Those envenomated mice treated with electric shock survived no better than the controls. We thus found no evidence that electric shocks crudely administered had any life saving effect in mice.
Animals↗
Observations on white and yellow venoms from an individual southern Pacific rattlesnake (Crotalus viridis helleri).
Biochemical differences in white and yellow venoms produced in the separate venom glands of an individual southern Pacific rattlesnake (Crotalus viridis helleri) were investigated. Compared to the yellow venom, the white venom contained fewer low molecular weight components and was considerably less toxic. Although the exact LD50 was not determined, the white venom did not produce toxic effects in mice when injected i.v. at concentrations up to 10 mg/kg. The i.v. LD50 of the yellow venom was approximately 1.6 mg/kg. Both white and yellow venoms had hemorrhagic activity, but the white venom caused less intradermal hemorrhage in mice. No L-amino acid oxidase activity was measured in the white venom and protease and phospholipase A2 activities of the white venom were much less than in the yellow venom. The white and yellow venoms both produced myonecrosis at 1, 3 and 24 hr after i.m. injection into mice, however, there were some qualitative differences in the myonecrosis produced. When the venom samples were reacted against Wyeth's polyvalent (Crotalidae) antivenom using immunodiffusion, three precipitin bands formed against the yellow venom, whereas only one formed against the white venom. When reacted against an antiserum to myotoxin alpha from C. viridis viridis venom, both the white and yellow venoms produced one precipitin band each.
Amino Acid Oxidoreductases↗
Calcium homeostasis in cows, with special reference to parturient hypocalcemia.
Calcium homeostasis is described in terms of controlled, disturbing, and controlling signals. Plasma calcium concentration [( Ca]p) and bone calcium mass (Mb) are the two main controlled signals. Disturbing signals include calcium intake (Vi) and clearance of plasma calcium to feces ( Clf ), bone (Clo+), placenta (Clp), and milk ( Clm ). Clo+ is a disturbing signal for [Ca]p and a controlling signal for Mb. Homeostasis is maintained by input control. Fractional renal calcium reabsorption (alpha r) decreases when calcium entry into plasma is excessive, but usually calcium entry rate (VT) responds effectively to small changes in [Ca]p associated with changes in disturbing signals. With increases in Vi, both fractional calcium absorption (alpha d) and fraction of bone calcium removed (lambda b) decrease to maintain VT at an appropriate level. As Clo+ declines with advancing age, [Ca]p rises slightly but VT decreases: a 1% change in [Ca]p would lead to a 13% change in VT. In heavily lactating cows, this response of VT may be enhanced. Parturient hypocalcemia may be the result of delayed negative feedback responses of lambda b (1 wk) and alpha d (1 day). Positive feedback between [Ca]p and gut motility may lead to transient suppression of VT during hypocalcemia, despite high plasma parathyroid hormone and 1,25-dihydroxyvitamin D3 concentrations. Parturient paresis is an example of a disordered accelerative response in a complex control system amenable to a variety of physiologically rational management procedures.
Absorption↗
The treatment of smoking as a self-defeating behavior.
This study (n = 18 men and women) sought to determine whether (a) the Eliminating Self-Defeating Behaviors Workshop would help smokers significantly decrease their smoking behavior, (b) this decrease would be maintained for four weeks, and (c) the Rotter I-E Scale could predict which smokers would show the most significant decrease and maintain this reduction. The results indicated that members of the experimental group made significant decreases in their smoking rates (p less than .001) and maintained this reduction for four weeks. The experimental group also made significant changes toward more internal locus of control at the conclusion of the workshop (p less than .10) but did not maintain this change at the four-week follow-up. The Rotter I-E Scale was unable to predict which individuals would show the most significant decrease in smoking rate and maintain this reduction.
Behavior Therapy↗
Interactive, touchscreen nutrition education system.
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Food Labeling↗