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Biomedical subjects

B Nelson

Publications and source records attributed to B Nelson.

At least 55 records · Page 3Linked to original sources

Probing collinearity bias in the close induction field.

The substrates of the Poggendorff illusion can be evaluated using as few as two line segments, a test segment whose collinearity is judged, and an induction segment which serves to bias that judgment. Previous research from this laboratory has shown that a very short induction segment can produce a substantial bias of perceived collinearity when it is centered at the tip of the test segment, and there is some evidence that the symmetry of this configuration affects the strength of this bias. Four experiments were conducted to clarify the issue of symmetry in the stimulation of the "half-field" zones which lie on each side of the tip. That Exp. 1a showed displacements which moved the induction segment to an eccentric position, i.e., occupying a single half-field, reduced collinearity error. With additional displacement which produced a gap there was a rebound of induction effect. Exp. 1b indicated that an eccentric induction segment does not produce the usual strength or pattern of bias as a function of its orientation relative to the test segment. Exp. 2a suggested that the strength of induction effect is a function of symmetry within the half-fields rather than the lengths of the segments per se. Finally, in Exp. 2b the strength of induction was a joint function of the position of a short segment within one half-field and the length of another segment which stimulated the other half-field. The effect showed a complex oscillation with changes in position. We discuss the induction mechanism as beginning with "contour filters" which register the induction segment(s) and which combine their responses on the basis of "tandem activation" of the close half-fields.

Form Perception↗

Discordant expression of Bcl-x and Bcl-2 by keratinocytes in vitro and psoriatic keratinocytes in vivo.

Apoptosis is a required event in maintaining kinetic homeostasis within continually renewing tissues such as skin. However, no systematic study of the apoptotic process in epidermal keratinocytes of the skin has been performed. In this report, we examined the expression of proteins associated with promoting (Fas) or preventing (Bcl-2, Bcl-x, CD40) apoptosis in the normal, psoriatic, and malignant keratinocyte. Immunohistochemical staining and flow cytometry analysis revealed that normal cultured keratinocytes express low levels of Fas, CD40, and Bcl-x that was enhanced by cytokines including gamma-interferon (IFN-gamma) and a phorbol ester tumor promoter, TPA. Only faint Bcl-2 staining was detected in cultured keratinocytes exposed to IFN-gamma and TPA compared with the prominent expression of Bcl-x. Biopsies of normal skin, psoriatic plaques, and basal cell carcinomas were examined to extend the in vitro observations. Immunohistochemical staining revealed that while keratinocytes in normal epithelium express low to absent levels of Fas and Bcl-x, psoriatic keratinocytes expressed significantly higher levels of Fas and Bcl-x. In contrast, malignant keratinocytes in basal cell carcinomas expressed high levels of Bcl-2, but minimal Bcl-x, and no Fas. Immunoblot analysis revealed that the long form of Bcl-x (Bcl-xI), which prevents apoptosis in lymphocytes, is expressed by cultured keratinocytes and psoriatic plaque keratinocytes. We conclude that normal cytokine-activated keratinocytes can express an apoptotic (Fas) and an anti-apoptotic protein (Bcl-x). The overexpression of Bcl-x in psoriasis, or Bcl-2 in basal cell carcinomas, may contribute to the longevity of these cells by blocking the normal apoptotic process involved in the terminal differentiation program of epidermal keratinocytes.

Adult↗

Caring and the health professions.

This study analyzes patient descriptions of what constitutes caring in the physician and nurse. We propose that health care students can be taught caring behavior through the use of patient narratives.

Humans↗

Recombinant endotoxin-binding protein (rBPI23) attenuates endotoxin-induced circulatory changes in humans.

In the present study the protective effect of a recombinant endotoxin-binding protein rBPI23 on the circulatory changes in experimental endotoxemia in humans was investigated. In a controlled, blinded crossover study, eight volunteers were challenged twice with an intravenous bolus injection of endotoxin (40 EU/kg body weight), and concurrently received either rBPI23 (1 mg/kg) or placebo (human serum albumin, 0.2 mg/kg). Hemodynamic parameters were obtained non-invasively by means of M-mode, two-dimensional, and Doppler echocardiography. rBPI23 significantly reduced indices of the endotoxin-induced hyperdynamic circulation. rBPI23 treatment significantly reduced increase in cardiac index (P = 0.0156). rBPI23 treatment diminished the endotoxin-induced decrease in systemic vascular resistance index (P = 0.0304). rBPI23 did not prevent the endotoxin-induced rise in body temperature and systolic, diastolic and mean arterial pressure were not significantly different in the rBPI23- and placebo-treatment arm. Both treatment periods showed a small reduction in end diastolic and end systolic volumes. rBPI23 treatment slightly reduced the increase in M-mode ejection fraction and fractional shortening. These results indicate that rBPI23 is capable of attenuating the potentially deleterious circulatory effects of endotoxin in humans.

Adult↗

Casemix--an AMA perspective.

The introduction of casemix payment systems into Australia's public hospitals is an inevitability which the Australian Medical Association has now begun to address. A greater involvement of clinicians in the design and implementation of casemix can add substantial quality to these systems. However, there is concern that a proliferation of separate casemix systems may be contrary to overall health policy developments and that governments will not understand the limits of casemix. Recent attempts to include medical payments within a casemix payment system in the private sector faced our united opposition. Finally, special care needs to be taken to ensure that the introduction of a casemix payment system does not further disadvantage access to high quality health care for Aborigines.

Australia↗

The 24-hour pattern of prolactin secretion in depressed and normal adolescents.

Plasma prolactin concentrations were measured at 20-min intervals over a 24-hr period in 49 adolescents with major depressive disorder (MDD) and 39 normal control adolescents. Neither the pattern nor the amount of prolactin secretion was significantly different between these two groups. There were significant gender differences, with girls secreting more prolactin than boys, but no significant gender-by-diagnosis interactions were found. With the possible exception of psychosis, dividing the MDD sample based on clinical characteristics failed to reveal differences. These findings are discussed in the context of changes in prolactin in childhood depression using a serotonergic challenge study, as well as in relation to baseline prolactin studies in adult depression.

Adolescent↗

Genetic modification of T cell clones to improve the safety and efficacy of adoptive T cell therapy.

Our laboratory has developed methods to isolate human antigen-specific cytolytic CD8+ T cell clones and to expand such clones in vitro to numbers sufficient for T cell therapy of human diseases. Studies in immunocompromised bone marrow transplant patients at high risk for disease associated with cytomegalovirus have demonstrated that administration of more than 10(9) CD8+ T cell clones is safe and can effectively reconstitute a deficient human immune response. Our laboratory is applying this strategy of adoptive therapy to the treatment of human cancer, starting with the subset of patients with Hodgkin's disease who show expression of proteins encoded by the Epstein-Barr virus in their malignant Reed-Sternberg cells. The development of efficient systems such as retroviral vectors for the introduction of genes into primary cells has made it possible to consider overcoming some of the limitations of the effector T cells that normally mediate response to an antigen. Our laboratory is attempting to modify T cell clones by the introduction of genes before transfer as a means to improve the safety and/or efficacy of T cell therapy.

Antigens, Viral↗

Cholinergic REM induction test with arecoline in depressed children.

Children with major depressive disorder often fail to exhibit electroencephalographic (EEG) sleep abnormalities similar to those reported in depressed adults. It was hypothesized that a cholinergic rapid eye movement (REM) induction test would contribute to the identification of EEG sleep abnormalities in depressed children. To test this hypothesis, prepubertal children meeting research diagnostic criteria for major depressive disorder (n = 33) and carefully screened healthy control children (n = 15) were enrolled in a 4-day psychobiologic protocol that included 1 night with infusion of arecoline (0.5 mg) during the first non-REM sleep period. Although there had been no significant group differences in baseline sleep measures, results on the arecoline night revealed significantly shorter REM latency in the group of depressed children compared with the control children (mean +/- SD = 105 +/- 51 minutes vs. 140 +/- 46 minutes). The design of the protocol (with an interval break immediately preceding the arecoline night) prevented a direct estimation of arecoline effects within subjects; however, these data provide promising preliminary results regarding cholinergic REM induction tests in childhood depression.

Aging↗

A human Alu RNA-binding protein whose expression is associated with accumulation of small cytoplasmic Alu RNA.

Human Alu sequences are short interspersed DNA elements which have been greatly amplified by retrotransposition. Although initially derived from the 7SL RNA component of signal recognition particle (SRP), the Alu sequence has evolved into a dominant transposon while retaining a specific secondary structure found in 7SL RNA. We previously characterized a set of Alu sequences which are expressed as small cytoplasmic RNAs and isolated a protein that binds to these transcripts. Here we report that biochemical purification of this protein revealed it as the human homolog of the SRP 14 polypeptide which binds the Alu-homologous region of 7SL RNA. The human cDNA predicts an alanine-rich C-terminal tail translated from a trinucleotide repeat not found in the rodent homolog, which accounts for why the human protein-RNA complex migrates more slowly than its rodent counterpart in RNA mobility shift assays. The human Alu RNA-binding protein (RBP) is expressed after transfection of this cDNA into mouse cells. Expression of human RBP in rodent x human somatic cell hybrids is associated with substantial increase in endogenous small cytoplasmic Alu and scB1 transcripts but not other small RNAs. These studies provide evidence that this RBP associates with Alu transcripts in vivo and affects their metabolism and suggests a role for Alu transcripts in translation in an SRP-like manner. Analysis of hybrid lines indicated that the Alu RBP gene maps to human chromosome 15q22, which was confirmed by Southern blotting. The possibility that the primate-specific structure of this protein may have contributed to Alu evolution is considered.

Amino Acid Sequence↗

Improving cash flow through benchmarking.

Healthcare organizations can use two benchmarking techniques to improve their accounts receivable departments' performance: 1) studying the accounts receivable statistics of model healthcare organizations, and 2) visiting these model organizations in order to get a first-hand look at how they do business. Employing these two benchmarking techniques can help healthcare organizations reduce gross days revenue outstanding, bad debt, the length of time between the date a patient is discharged and the date a bill is mailed, the total percentage of receivables more than 90 days old, and general business office expenses related to collection.

Accounts Payable and Receivable↗

Effects of administration of an anti-CD5 plus immunoconjugate in rheumatoid arthritis. Results of two phase II studies. The CD5 Plus Rheumatoid Arthritis Investigators Group.

OBJECTIVE: To evaluate the safety and activity of an immunoconjugate of ricin A chain and anti-CD5 monoclonal antibody (anti-CD5 IC), with and without concomitant methotrexate and/or azathioprine, in the treatment of rheumatoid arthritis (RA). METHODS: Seventy-nine patients with active RA were enrolled in 2 prospective open-label protocols. RESULTS: Using composite criteria, response rates were 50-68% at 1 month and 22-25% at 6 months. Transient depletion of CD3/CD5 T cells was observed on days 2 and 5 of treatment, with reconstitution on day 15 or day 29. Treatment-associated adverse effects were common but resolved rapidly without sequelae. CONCLUSION: These findings suggest activity of anti-CD5 IC in active RA and warrant confirmation in a multicenter randomized study (currently underway).

Adult↗

The psychosocial functioning and family environment of depressed adolescents.

OBJECTIVE: This study examined measures of functional impairment and family relations in a sample of 62 adolescents with major depressive disorder (MDD) and 38 normal controls with no history of psychiatric illness. METHOD: Ratings of the following domains were obtained: mother-child relations, father-child relations, spousal relations, sibling relations, peer relations, and school performance. Ratings of each domain for the 3-month period preceding the assessment were derived from information obtained using a semistructured interview administered independently to the adolescents and one of their parents. RESULTS: Adolescents with MDD were found to have severe difficulties in all areas. Ninety percent of the depressed adolescents had scores greater than 2 SD above the mean of the normal controls on one or more of the domain ratings. In addition, adolescents with difficulties in parent-child relations were more likely than those adolescents without problems in family relations to have difficulties in peer relations and school performance. CONCLUSIONS: The authors discuss the importance of systematically examining psychosocial variables in future studies of the etiology, course, and treatment of MDD in adolescents.

Adolescent↗

Healthcare reform adds complexities for today's CFO.

The profile of the typical senior financial executive in a hospital or corporate healthcare setting has changed little over the past two years. A November 1992 survey of CFOs by HFMA and Zimmerman & Associates, Inc., which updates a similar survey conducted in 1990, showed that the typical healthcare CFO is an extremely busy 41-year-old male with a postgraduate education who has held the position of CFO for six years. Survey findings also reveal that the CFO title is the predominant title for senior financial executives in healthcare facilities. For those receiving incentive compensation, the average compensation in 1992 was 11.7 percent of base salary. Within the context of career advancement, the CFO is most interested in learning more about healthcare reform; declining operating margins was seen as the CFO's most significant career challenge.

Adult↗

Patient accounts managers prepare for change.

Automated data processing and electronic data interchange have become necessary and increasingly vital aspects of the processes of admission, registration, billing, and collection. A recent survey of patient accounts managers found they feel they may need to improve their technical skills to meet future challenges.

Data Collection↗

Retention can be improved!

A unique program has been developed to encourage retention of nurses who prefer to remain in direct patient care roles. Both recognition and monetary reward are available to nurses who join the "Professional Excellence in Nursing" (PEN) program. The underlying philosophy is that stable employment, clearly defined and attainable goals and recognition for a higher level of performance are keys to job satisfaction--and thus to retention. Evaluative data on this young program are not available but informal surveys indicate a positive outcome.

Career Mobility↗