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Biomedical subjects

J Jackson

Publications and source records attributed to J Jackson.

At least 217 records · Page 12Linked to original sources
PubMed1989

IL-3 and stromal cell-derived factor synergistically stimulate the growth of pre-B cell lines cloned from long-term lymphoid bone marrow cultures.

The addition of IL-3 to modified Whitlock-Witte long-term lymphocyte cultures was found to enhance the growth of a small but significant number of B cell precursors supported by an adherent stromal cell monolayer. Several pre-B cell lines were cloned from IL-3-treated long-term lymphocyte cultures. The growth requirements and physical properties of one representative clone, BL/3, are described. BL/3 cells were shown to be unresponsive to IL-3 except when it is used at very high concentrations. In contrast, significant growth was stimulated by stromal cell conditioned medium previously shown to contain a pre-B cell growth factor. Optimal growth of the pre-B cell clone was stimulated by stromal cell conditioned medium plus IL-3. Synergy between the stromal cell-derived factor and IL-3 occurred when IL-3 was used over a wide range of concentrations including a relatively low amount that was ineffective as a growth stimulus by itself. The finding that more than one factor is required to sustain optimal growth of some pre-B cells parallels the complex growth requirements reported for some primitive myeloid/erythroid progenitors.

Animals↗
PubMed1989

Low-frequency restoration.

In magnetic resonance imaging, if the object of interest is known to be spatially bounded within the image field-of-view, then the high-intensity, low spatial frequencies can be determined by postprocessing. This allows the system receiver gain to be increased, thereby decreasing the quantitation noise from the analog-to-digital converters. No imaging sequence modifications are required.

Animals↗
PubMed1989

An investigation of factors affecting progress of patients on a stroke unit.

The aim of the study was to identify factors affecting the progress in physical abilities and activities of daily living of patients admitted to a stroke unit. A series of 70 patients admitted consecutively were assessed on a series of tests of motor, functional and cognitive abilities at admission. They were assessed for level of motor abilities and activities of daily living at discharge and 9 months after stroke. Predictive equations were developed which account for between 61% and 33% of the variance in motor abilities and activities of daily living at discharge and at 9 months after stroke. The most important factor influencing outcome was the degree of motor loss.

Activities of Daily Living↗
PubMed1989

Autoantibody facilitated cleavage of C1-inhibitor in autoimmune angioedema.

C1-inhibitor (C1-Inh) is an important inhibitor of the inflammatory response and deficiency of this inhibitor, which may be hereditary or acquired, is associated with recurrent episodes of edema. Recently, an autoimmune form of angioedema has been described that is associated with functional deficiency of C1-Inh and an autoantibody that impedes C1-Inh function. In this report we describe the isolation of C1-Inh from the monocytes and plasma of a patient with autoimmune angioedema and demonstrate that the patient's monocytes secrete structurally and functionally normal C1-Inh, but show that this protein circulates in the patient's plasma in an inactive, structurally altered form. Furthermore, using analytic gel electrophoresis techniques it is demonstrated that the patient's autoantibody facilitates cleavage of normal C1-Inh, by its target proteases, to the same species of C1-Inh that is found circulating in the patient's plasma. This autoantibody facilitated cleavage of normal C1-Inh is apparently a consequence of destabilization of protease/inhibitor complexes. These findings contribute to our understanding of protease/C1-Inh interactions and document important observations on pathogenic mechanisms in autoimmune disease.

Angioedema↗
PubMed1989

Fluorescence polarization immunoassay of urinary 5-hydroxy-3-indoleacetic acid.

Fluorescence polarization immunoassay of 5-hydroxy-3-indoleacetic acid in urine is described and compared with liquid chromatography (electrochemical detection) and colorimetry. Reports of in-house performance data and results of clinical trials are included to emphasize the usefulness of the assay for routine work.

Chromatography, High Pressure Liquid↗
PubMed1989

Induced differentiation of murine erythroleukemia cells (MELC) by polar compounds: marked increased sensitivity of vincristine resistant MELC.

Hexamethylene bisacetamide (HMBA) is a most effective compound as an inducer of MELC differentiation. HMBA-mediated terminal differentiation of MELC is a multistep process. There is a latent period during which a number of changes occur including the appearance of Ca2+ and phospholipid independent PKC activity in the cytosol, and modulation in expression of several genes, including c-myc, c-myb, c-fos and the p53 genes. During this latent period there is neither detectable commitment to terminal differentiation (including terminal cell division) or increased transcription of the globin genes. HMBA-mediated commitment to terminal differentiation is first detected at about 12 hr and increases in a stochastic fashion, until over 95% of the population has been recruited to terminal differentiation by 48 to 60 hr. Commitment is associated with persistent HMBA-mediated suppression of c-myb gene expression. By 36 to 48 hr, transcription of the globin genes has increased by 10 to 30 fold, whereas transcription of rRNA genes is suppressed. The steroid, dexamethasone, and the tumor promotor, phorbol-12-myristate-13-acetate, suppress HMBA-induced MEL cell terminal differentiation. The evidence indicates that these agents act at a late step during the latent period. Recently, we showed that MELC variants selected for resistance to vincristine have a marked increased sensitivity to HMBA. Compared to the parental MELC strains, vincristine resistant MELC are: A) responsive to 1/5 to 1/10 the concentration of HMBA; B) induced to terminal differentiation without a latent period and C) resistant to inhibition of HMBA induced terminal differentiation by dexamethasone or tumor promotor. The vincristine resistant MELC have characteristics of the multidrug resistant phenotype. A number of independently derived vincristine resistant MELC lines show similar altered response to HMBA. These findings suggest that vincristine resistance leads to a constitutive expression of a factor or factors induced by HMBA in vincristine sensitive (wild type) MELC during the latent period and which are essential to the transition to terminal differentiation.

Acetamides↗
PubMed1989

Incorporating hard boxes and soft bubbles into the dietetics curriculum.

Dietitians have been challenged to learn the skills of creative thinking in order to become proficient managers in a rapidly changing world. We reviewed the literature to determine the prerequisites of creative thinking and assessed the management and administrative dietetics curriculum for our dietetic internship to determine whether those prerequisites were being met. A major concern in the dietetics profession is that students are not being adequately prepared to assume top management positions. A review of business school curriculums reveals that an emphasis on management theory and quantitative analysis does not adequately prepare students to function effectively in a world where creative problem solving is required. Effective managers at high levels of responsibility rely on intuition and hunches in addition to logical thought processes. Two thinking models are employed by managers--a rational one (hard box) and an intuitive one (soft bubble). These thinking models, or cognitive styles, can also be defined as left and right brain skills. Effective managers use left and right brain skills plus a combination of the two, or integrative brain skill. We reviewed the competencies, behavioral objectives, and planned experiences for the management level rotations of our dietetic internship to develop a conceptual model for the use of right, left, or integrative thought processes. We discovered that although integrative brain skills are used at all levels of our management rotations, especially the top management rotation, no rotation exclusively fosters right-brain skill development. A dietetic internship offers a fertile environment for developing the creative problem-solving skills that are required in management positions in the health care profession today.(ABSTRACT TRUNCATED AT 250 WORDS)

Administrative Personnel↗
PubMed1989

Direct immunofluorescence testing of skin biopsies--an under-utilised diagnostic aid.

Direct immunofluorescence testing of skin biopsies is a simple inexpensive and relatively non-invasive diagnostic procedure currently widely used in dermatological practice for the investigation and diagnosis of dermatological and immunological disorders. This paper reviews the value and applicability of the procedure in a variety of disease states. The sensitivity and specificity of the test to a spectrum of clinical conditions should encourage its more widespread use in general medical and rheumatology practice.

Biopsy↗
PubMed1989

Prognostic importance of the pre-B-cell immunophenotype and other presenting features in B-lineage childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study.

We report the prognostic significance of the pre-B-cell immunophenotype and other presenting features, including blast cell karyotype, in a randomized clinical trial conducted from 1981 to 1986 for children with early pre-B (n = 685) or pre-B (n = 222) acute lymphoblastic leukemia (ALL). Patients greater than or equal to 1 year and less than or equal to 21 years of age who attained complete remission were stratified by conventional risk criteria and immunophenotype and then randomized to receive continuation therapy with either of two regimens of intensive chemotherapy, designated S (standard) and SAM (standard plus intermediate-dose methotrexate, 1 g/m2 every 8 weeks). The proportions of subjects achieving complete remission in the two phenotypically defined subgroups were identical, 96%. At a median follow-up time of 42 months, the overall probability of 4-year event-free survival (+/- SE) was 63% +/- 2% (pre-B = 51% +/- 5% and early pre-B = 66% +/- 3%). Children with pre-B ALL had significantly shorter durations of continuous complete remission (P = .0004); this association included both bone marrow and CNS remissions (P = .0004 and P = .02, respectively). In a univariate Cox regression analysis of potentially important prognostic factors, the pre-B immunophenotype was significantly related to a poorer outcome, as were other recognized biologic and clinical features (eg, pseudodiploidy, older age, male sex, black race, and a higher WBC). It retained its prognostic strength in a multivariate model based on age, WBC, ploidy, and sex. The risk of failure at any point in the clinical course of a child with the pre-B immunophenotype was 1.8 times as great as that in a patient lacking this feature but otherwise having an equivalent risk status. It should be stressed that the predictive value of any of the significant characteristics identified in this study could diminish in the context of another, more effective treatment program. Nevertheless, our major conclusion, that children with pre-B ALL fare worse than those with early pre-B disease in a contemporary clinical trial has implications for stratified randomization of patients and the design of risk-specific treatment protocols.

Analysis of Variance↗
PubMed1989

An evaluation of Fecatwin/Feca EIA; a faecal occult blood test for detecting colonic neoplasia.

A combination guaiac and immunological test Fecatwin/Feca EIA for the detection of faecal occult blood was used in the investigation of 535 symptomatic patients in order to assess the value of this combined test in the detection of colorectal neoplasia. The addition of the immunological part of the test led to an improvement in specificity for colorectal cancer from 80% to 91% and an increase in the positive predictive value of the test for colorectal cancer from 14% to 24%. However, there was a fall in sensitivity from 75% to 67%. There was no substantial advantage in the addition of the immunological part of the test to justify the extra laboratory workload incurred.

Colonic Neoplasms↗
PubMed1988

A study of nurses' attitudes towards associate degree nursing students.

The purpose of this study was to examine the attitudes of staff nurses towards associate degree (AD) nursing students. The null hypothesis stated there will be no significant difference in the attitudes of staff nurses towards AD nursing students and associated concepts (nursing education, patient, physician, work, nurse.) The staff nurse's value as a role model is held in high regard yet little regard is given to her attitudes towards students. Through better understanding of staff nurses' attitudes, nurse educators can better plan, develop and coordinate clinical activities to provide an optimum learning environment. The findings showed the concept AD nursing student was significantly different from the rest, indicating a less positive attitude towards the AD nursing student than the related concepts. Implications for nursing practice are threefold. Nurse administrators must create an atmosphere and a philosophy which support the educational process within their institution, and recognize nurses' attitudes towards students. Practising nurses should examine their attitudes and willingness to work with students if their hospital offers their agency as a clinical facility. Educators must look closely at the units they assign students to, continually maintaining the lines of communication between staff nurses and clinical instructors. As service and education work together a quality environment can be provided in which there is optimum learning for the student. Both groups then contribute to the future of professional nursing.

Adolescent↗
PubMed1988

Intracellular pH, lactate, and energy metabolism in neonatal brain during partial ischemia measured in vivo by 31P and 1H nuclear magnetic resonance spectroscopy.

Sequential 31P and 1H nuclear magnetic resonance spectra were measured for neonatal piglets (n = 7) to determine the relationship between brain intracellular pH (pHi), lactate, and phosphorylated energy metabolites during partial ischemia. Simultaneous determinations of arterial and cerebral venous blood gases, pH, O2 content, and plasma concentrations of glucose and lactate were also made. Ischemia, induced by bilateral carotid artery ligation plus hemorrhagic hypotension for 35 min, resulted in variable reductions in ATP, phosphocreatine, and increases in Pi, H+, and lactate relative to control levels. In four piglets, whose arterial blood glucose rose above control, brain lactate exceeded 20 mumol g-1 with corresponding decreases in pHi of greater than 0.7 units compared to control levels. The extents of brain acidosis and lactosis showed a strong linear correlation with each other (r = 0.94). Maximal changes in brain lactate, pHi, and ATP at the end of ischemia showed significant positive linear correlations with the control levels of arterial blood glucose, but did not correlate with arterial glucose or arterial cerebral-venous glucose difference values during ischemia. The relationship between pHi and buffer base deficit was comparable to results reported for adult animals up to 20 mumol ml-1. However, in contrast to models proposed for adult brain, the continued linear relationship between pH and higher buffer base levels is most consistent with a theoretical model that assumes the presence of weak acid buffers with pKa values from 6.7 to 5.2.

Adenosine Triphosphate↗