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C J Hogan

Publications and source records attributed to C J Hogan.

At least 19 recordsLinked to original sources
PubMed2001

Development and reproducibility of a brief food frequency questionnaire for assessing the fat, fiber, and fruit and vegetable intakes of rural adolescents.

OBJECTIVE: To describe the systematic development and reproducibility of a food frequency questionnaire (FFQ) designed to meet the specific research requirements of the Goals for Health cancer prevention intervention program for rural middle school children. DESIGN: A 4-step process was used to develop a brief FFQ for scoring intakes of total fat, fiber, and fruits and vegetables. The resulting questionnaire consisted of 25 food frequency items and 10 supplemental questions. Reproducibility of the questionnaire was determined by comparing responses at the beginning and end of a 4-month interval. SUBJECTS: Study subjects were sixth- and seventh-grade students attending middle schools in rural areas of Virginia and upstate New York. Seventh-grade students participated in the pilot study, and sixth-grade students participated in the reproducibility study. The final version of the FFQ was completed twice by 539 sixth graders. After exclusions for missing and unreliable data, the usable sample size was 415. Boys were somewhat more likely than girls to be excluded for missing data. African-American students comprised 32% of the population. STATISTICAL ANALYSES PERFORMED: Each food frequency item was associated with 3 scores--a fat score, a fiber score, and a combined score for the number of servings of fruits and vegetables. Means and standard deviations were determined for nutrient variables, differences between repeat administrations were tested for significance by paired t test, and Pearson correlation coefficients were calculated for nutrients and for individual food items. RESULTS: Correlation coefficients for nutrient scores were 0.58 for fat, 0.49 for fiber, and 0.51 for fruits and vegetables. For individual food items, correlations ranged from 0.24 to 0.59 (mean=0.41). APPLICATIONS/CONCLUSIONS: Using a systematic approach to developing a study-specific FFQ for rural adolescents is feasible. Further, the reproducibility of the Goals for Health questionnaire was demonstrated for the 3 nutrient scores it was designed to measure. This developmental approach may be readily adapted to other populations, study designs, and nutrients of interest. The validity of the questionnaire remains to be tested.

Adolescent↗
PubMed2001

Minimal residual disease (MRD) in remission t(8;21) AML and in vivo differentiation detected by FISH and CD34+ cell sorting.

Many patients with t(8;21) AML have residual positive cells during remission. We previously developed D-FISH probes that detect both derivative chromosomes and the normal alleles. In negative controls, only 2/44,000 (0.0045%) positive signals were observed. To investigate MRD, we examined specimens from 29 patients who had initially obtained CR. In remission patients, 61% had 1-4/2000 positive cells (0.05-0.19%). Higher frequencies were found in two patients in early relapse and in one patient in early remission. However, a negative test did not exclude relapse. Since false positives were negligible and because most t(8;21) AMLs express CD34, we asked whether cell sorting combined with FISH would increase the sensitivity. In one patient, we observed that 80% of CD34+ cells were t(8;21)+ at 2 months from initial clinical and cytogenetic remission. However, by 5 months the pre- and post-sorted populations contained 0.15% and 0.06% t(8;21) cells, respectively. Whereas essentially all t(8;21) cells in the initial specimen expressed CD34, only 0.6% were subsequently CD34+. These results are consistent with in vitro assays showing that residual t(8;21) cells undergo differentiation. Thus, FISH can identify MRD in a majority of t(8;21) patients and, combined with CD34+ selection, may provide an indirect assessment of the differentiation state of residual t(8;21) cells.

Acute Disease↗
PubMed2001

Progressive articular cartilage loss following radiofrequency treatment of a partial-thickness lesion.

Arthroscopic debridement of partial-thickness articular cartilage lesions is a common orthopaedic procedure. Radiofrequency treatment has rapidly gained clinical acceptance despite the lack of prospective studies involving second-look arthroscopy to determine long-term sequelae. We report a case in which a partial-thickness lesion that had been treated with radiofrequency ablation showed progressive thinning of the articular surface.

Adult↗
PubMed2001

Coagulation studies in preoperative neurosurgical patients.

Unselected preoperative coagulation testing is known to have low positive yield. However, no study has specifically evaluated neurosurgical patients. A retrospective study of 1211 patients having neurosurgery over a one-year period was therefore conducted. Preoperative test results (activated partial thromboplastin time [aPTT], prothrombin time [PT] and platelet count) and historical factors indicating a potential bleeding tendency were recorded. Abnormality was defined as a test result outside the normal range for our laboratory. Seventeen per cent of all test results were abnormal. However, if abnormality was redefined as a test result indicating potential bleeding tendency (low platelet count, prolonged aPTT and/or PT), only 7.2% of results were abnormal. Many patients had factors on history indicating a potential bleeding tendency, but only a prolonged aPTT, cranial surgery and the use of anti-hypertensive and anaesthetic drugs preoperatively predicted postoperative bleeding. Prolonged aPTT was predictable on history in most patients. We conclude that routine screening of all preoperative neurosurgical patients in our hospital is unnecessary.

Blood Coagulation↗
PubMed2001

An orthopedic surgeon's guide to interpreting electromyography.

Electrodiagnostic tests such as electromyography (EMG) and nerve conduction velocity studies are commonly ordered during the evaluation of patients with suspected peripheral nerve compression. Although these tests are invaluable extensions of the physical examination, many physicians are unable to interpret the test results, and so they base their operative decisions on electromyographers' impressions. A systematic approach to EMG interpretation allows surgeons to determine the nature and location of lesions as well as the degree of involvement and the viability of affected skeletal muscles.

Electromyography↗
PubMed2000

Cosmic discord.

Explore the source record for details and available documents.

News↗
PubMed1997

Engraftment and development of human CD34(+)-enriched cells from umbilical cord blood in NOD/LtSz-scid/scid mice.

Understanding the repopulating characteristics of human hematopoietic stem/progenitor cell fractions is crucial for predicting their performance after transplant into high-risk patients following high-dose therapy. We report that human umbilical cord blood cells, 78% to 100% of which express the hematopoietic progenitor cell surface marker CD34, can consistently engraft, develop, and proliferate in the hematopoietic tissues of sublethally irradiated NOD/LtSz-scid/scid mice. Engraftment and development of CD34+ cells is not dependent on human growth factor support. CD34+ cells home to the mouse bone marrow (BM) that becomes the primary site of human hematopoietic development containing myeloid, lymphoid, erythroid, and CD34+ progenitor populations. Myeloid, and in particular lymphoid cells possessing more mature cell surface markers, comprise the human component of mouse spleen and peripheral blood, indicating that development proceeds from primary hematopoietic sites to the periphery. Repopulation of secondary recipients with human cells by BM from primary recipients demonstrates the maintenance of substantial proliferation capacity of the input precursor population. These data suggest that the cells capable of initiating human cell engraftment (SCID-repopulating cells) are contained in the CD34+ cell fraction, and that this mouse model will be useful for assaying the developmental potential of other rare human hematopoietic cell fractions in vivo.

Animals↗
PubMed1997

Ex vivo expansion of megakaryocyte progenitors: effect of various growth factor combinations on CD34+ progenitor cells from bone marrow and G-CSF-mobilized peripheral blood.

Prolonged thrombocytopenia resulting from inadequate megakaryocyte (MK) progenitor cell reconstitution is a serious complication of hematopoietic cell-supported high-dose chemotherapy (HDC). In this situation, the infusion of MK progenitors that are expanded ex vivo could be clinically beneficial. In this study we investigated the ability of various growth factor combinations to generate MK progenitors. CD34+ cells derived from bone marrow (BM) and granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood (PB) from 17 patients with breast cancer, lymphoma, or myeloma were cultured unpertubed for 10 days in a serum-free liquid culture system that contained recombinant growth factors. Five different growth factors combinations were evaluated: Stem cell factor (SCF), interleukin (IL)-3, IL-6 + G-CSF (combination 1); SCF, megakaryocyte growth and development factor (MGDF) + G-CSF (combination 2); SCF + MGDF (combination 3); MGDF alone (combination 4); and SCF, IL-3, IL-6, G-CSF + MGDF (combination 5). PB CD34+ cells yielded significantly higher numbers of CD41+ MK progenitors than BM CD34+ cells with any of the growth factor regimens assayed. PB CD34+ cells (2x10[5]) at day 0 generated 1.2 to 1.3x10(6) CD41+ cells by day 10 when cultured in the presence of growth factor combinations 1, 2, or 3. In contrast, 2x10(5) BM CD34+ cells produced 5x10(5) CD41+ cells after 9 days in the presence of combination 1, whereas lower numbers of CD41+ cells were generated in cultures with combinations 2 and 3 (2.3x10[5] and 4.2x10[4], respectively). The addition of MGDF to cultures that were grown with combination 1 for 5 days increased the number of CD41+ cells (1.7-fold increase in PB-derived cultures, 1.6-fold increase in BM-derived cultures). Treatment with MGDF alone resulted in higher frequencies of MK progenitors than those obtained in cultures with combined growth factors (79% in PB-derived cultures, 25% in BM-derived cultures), but because total cell growth was attenuated, absolute numbers of MK progenitors were lower (7x10(5) in PB-derived cultures, 7x10(4) in BM). Morphological analysis of immunocytochemically identified megakaryocytic cells revealed mononuclear cells as the predominant cell type in all of the cultures. During the 10-day culture period, PB-derived MK progenitors did not show notable maturation, even under the influence of MGDF, whereas in BM-derived cultures MGDF induced a significant shift to binuclear cells and stage I MK after day 5. Phenotypic analysis of cell surface markers showed that the majority of cultured megakaryocytic cells coexpressed CD34 and platelet glycoproteins (GPs), also indicating an immature stage of development. The ex vivo proliferative activity of CD34+ cells and their potential to develop into the megakaryocytic lineage demonstrated considerably high interpatient variations. There was no correlation between platelet recovery following HDC with hematopoietic cell support and the magnitude of GP+ cell expansion ex vivo, suggesting the feasibilty of MK expansion ex vivo in patients with prolonged thrombocytopenia posttransplantation. In summary, these data indicate that GCSF-mobilized CD34+ PBPCs are more effectively expanded ex vivo into the megakaryocytic lineage than are CD34+ BMPCs. CD34+/GP+ MK progenitors may be an appropiate cell population for transplantion as prophylaxis or treatment of prolonged thrombocytopenia. The efficacy of this procedure will be tested prospectively in a clinical trial.

Adult↗
PubMed1997

Multilineage engraftment in NOD/LtSz-scid/scid mice from mobilized human CD34+ peripheral blood progenitor cells.

Peripheral blood progenitor cells (PBPCs) are now the most widely used source for hematopoietic support of patients in the autologous transplant setting and are increasingly being used for allogeneic transplantation. A reliable model to characterize the in vivo potential of various PBPC subpopulations could be valuable as a preclinical assay to predict the hematopoietic performance in humans of these populations and of products resulting from their manipulations ex vivo. We have used immunocompromised nonobese diabetic/LtSz-scid/scid (NOD/SCID) mice to engraft human CD34+ PBPCs and to study the repopulation characteristics of this progenitor cell fraction. Following myeloablation, intravenous infusion of CD34+ cells consistently produced engraftment and development in mice. Multilineage development occurred in all mice with CD34+ cells, erythroid precursors, and the most immature populations of myeloid cells and B lymphocytes restricted to the mouse bone marrow (BM). More mature populations of myeloid cells and B lymphocytes were peripheralized to the spleen and blood of the animals. This finding suggests that human hematopoiesis in the mice may recapitulate hematopoietic recovery in humans. The provision of human growth factors was not necessary for either engraftment or development of CD34+ cells. When mice were supplemented with growth factors, engraftment levels were unaffected but development was biased toward myeloid production. These findings indicate that providing nonphysiological levels of human growth factors may obscure or enhance the developmental potential of particular progenitor cell populations in this model. Cells capable of initiating colony formation in vitro were maintained in BM during the engraftment period (up to 17 weeks), suggesting that continuous production of myeloid and erythroid precursors occurred from more primitive hematopoietic cells subsequent to engraftment. In comparing results from this study with previous results, it was found that in this model the engraftment potential of CD34+ umbilical cord blood cells is greater than that described here for CD34+ PBPCs. In summary, this model may provide a reliable assay to predict the hematopoietic potential of progenitor cell populations in humans if a correlation for engraftment of identical cell fractions can be established between the two species.

Animals↗
PubMed1996

The history of the galaxies.

Astronomical observations now reach far enough back in time, in enough depth and detail, to reveal the history of galaxies since their formation. The early Universe contained a network of gas clouds that filled much of the space between the young galaxies, where stars were forming at a high rate. Since then, intergalactic space has been swept clean, and galaxies have continued to convert the dwindling supply of gas slow into stars.

Astronomical Phenomena↗
PubMed1995

Large volume ex vivo expansion of CD34-positive hematopoietic progenitor cells for transplantation.

A large volume culture system was developed for the ex vivo expansion of CD34 positive (+) hematopoietic progenitors, using cell donated by 15 patients receiving high-dose chemotherapy with autologous hematopoietic progenitor cell support (AHPCS). Substantial expansion of myeloid (181-fold) and megakaryocyte (41-fold) progenitors cells was demonstrated, using the conditions that we determined to be optimal: CD34+ progenitors cultured unperturbed for 7 (marrow) or 10 (blood) days in Teflon-coated bags with X-Vivo-10 medium containing 10% autologous plasma, 100 ng/ml, respectively, of recombinant stem cell factor (SCF), interleukin 3 (IL-3), interleukin 6 (IL-6), and granulocyte colony-stimulating factor (G-CSF). The studies demonstrated that (a) CD34 selection was necessary to obtain large, clinically relevant numbers of hematopoietic progenitors, (b) the addition of G-CSF to the baseline regimen of SCF/IL-3/IL-6 significantly enhanced the expansion of myeloid progenitors, (c) the addition of IL-1 to SCF/IL-3/IL-6 did not significantly enhance myeloid progenitor cell expansion, (d) CD34+ G-CSF-mobilized peripheral blood progenitor cells (PBPC) produced higher numbers of myeloid progenitors in culture than CD34+ marrow cells, and (e) long-term tissue culture (LTC) assays demonstrate the preservation of long-term initiating cells in ex vivo culture. The short-term and long-term reconstituting capability of CD34+ PBPC cultured in this system remains to be determined and will be evaluated in a clinical trial where they will be used as the sole source of AHPCS following high-dose therapy.

Antigens, CD34↗
PubMed1993

Inhibition of anaphase spindle elongation in vitro by a peptide antibody that recognizes kinesin motor domain.

Isolated central spindles or spindles in detergent-permeabilized cells from the diatom Cylindrotheca fusiformis can undergo ATP-dependent reactivation of spindle elongation in vitro. We have used a peptide antibody raised against a 10-amino acid portion common to the kinesin superfamily motor domain to look for kinesin-like motor activity during anaphase B of mitosis. The peptide antibody localizes to central spindles. Upon ATP reactivation of spindle elongation, antigens recognized by the antibody are associated exclusively with the central spindle midzone where antiparallel microtubules of each half-spindle overlap. The antibody recognizes several polypeptides by immunoblot using isolated spindle extracts. One of these polypeptides behaves like kinesin with respect to nucleotide-specific binding to and release from taxol-stabilized microtubules. Preincubation of the spindle model with the peptide antibody inhibits subsequent ATP reactivation of spindle elongation. Coincubation of the peptide antibody with peptide antigen rescues spindle function. These results support a role for kinesin-related protein(s) in spindle elongation (anaphase B) of mitosis and suggest that one or several polypeptides that we have identified in spindle extracts may fulfill this function.

Adenosine Triphosphate↗
PubMed1992

Developmental changes in tritium autoabsorption.

Developmental changes in autoabsorption of tritium emissions were examined in 30 brain regions in the rat at Postnatal Days 0, 4, 7, 10, 14, 21, and 28 and adulthood. Rats received tritiated 2-deoxyglucose in vivo. Alternate brain sections were extracted in chloroform, and autoradiographs were developed from extracted and nonextracted sections. The ratio of optical density values in extracted vs nonextracted sections was used to determine autoabsorption for each structure. Three principal temporal patterns in the development of adult levels of autoabsorption, determined by the optical density ratios, were identified: (1) a minimal increase pattern in which autoabsorption rose only slightly between birth and adulthood; (2) a plateau pattern in which a rapid early increase was followed by stable values; and (3) a late increase pattern in which autoabsorption remained relatively constant until Postnatal Day 28, with a large increase between Day 28 and adulthood. In addition, optical density ratios fluctuated during the second postnatal week in close to one-third of the structures. The data suggest that developmental events affecting the ratio of gray to white matter produce substantial local variations in the development of adult levels of autoabsorption that are distinct for each structure. To correct for autoabsorption effects in ontogenetic studies using tritium autoradiography, it is necessary to determine directly the degree of autoabsorption at a particular time point for the structure of interest. Our results indicate that the technique of in vivo administration of tritiated 2-deoxyglucose followed by chloroform extraction appears to be a sensitive and reproducible method for assessing autoabsorption at all ages.

Absorption↗
PubMed1992

Physiological evidence for involvement of a kinesin-related protein during anaphase spindle elongation in diatom central spindles.

We have developed a new model system for studying spindle elongation in vitro using the pennate, marine diatom Cylindrotheca fusiformis. C. fusiformis can be grown in bulk to high densities while in log phase growth and synchronized by a simple light/dark regime. Isolated spindles can be attained in quantities sufficient for biochemical analysis and spindle tubulin is approximately 5% of the total protein present. The spindle isolation procedure results in a 10-fold enrichment of diatom tubulin and a calculated 40-fold increase in spindle protein. Isolated spindles or spindles in permeabilized cells can elongate in vitro by the same mechanism and with the same pharmacological sensitivities as described for other anaphase B models (Cande and McDonald, 1986; Masuda et al., 1990). Using this model, in vitro spindle elongation rate profiles were developed for a battery of nucleotide triphosphates and ATP analogs. The relative rates of spindle elongation produced by various nucleotide triphosphates parallel relative rates seen for kinesin-based motility in microtubule gliding assays. Likewise ATP analogs that allow discrimination between myosin-, dynein-, and kinesin-mediated motility produce relative spindle elongation rates characteristic of kinesin motility. Also, isolated spindle fractions are enriched for a kinesin related protein as identified by a peptide antibody against a conserved region of the kinesin superfamily. These data suggest that kinesin-like motility contributes to spindle elongation during anaphase B of mitosis.

Adenosine Triphosphate↗
PubMed1992

Isolation of a sea urchin egg kinesin-related protein using peptide antibodies.

To understand the roles of kinesin and its relatives in cell division, it is necessary to identify and characterize multiple members of the kinesin superfamily from mitotic cells. To this end we have raised antisera to peptides corresponding to highly conserved regions of the motor domains of several known members of the kinesin superfamily. These peptide antibodies react specifically with the motor domains of kinesin and ncd protein, as expected, and they also react with several polypeptides (including kinesin heavy chain) that cosediment with microtubules (MTs) precipitated from AMPPNP-treated sea urchin egg cytosol. Subsequent fractionation of ATP eluates of these MTs yields a protein of relative molecular mass 330 x 10(3) that behaves as a complex of three polypeptides that are distinct from conventional kinesin subunits or fragments thereof. This complex contains 85 kDa and 95 kDa polypeptides, which react with our peptide antibodies, and a 115 kDa polypeptide, which does not. This triplet of polypeptides, which we refer to as KRP(85/95), binds to purified sea urchin egg tubulin in an AMPPNP-enhanced, ATP-sensitive manner and induces the formation of microtubule bundles. We therefore propose that the triplet corresponds to a novel sea urchin egg kinesin-related protein.

Adenosine Triphosphate↗