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Biomedical subjects

D Harper

Publications and source records attributed to D Harper.

At least 19 recordsLinked to original sources
PubMed2006

Disposition of emergency department patients with psychiatric comorbidity: results from the 2004 National Hospital Ambulatory Medical Care Survey.

BACKGROUND: Few emergency department (ED) studies have examined how psychiatric comorbidity relates to hospitalisation decisions. METHODS: We assessed the relationship of psychiatric comorbidity to hospitalisation decisions among ED patients in the 2004 National Hospital Ambulatory Medical Care Survey. RESULTS: Patients with psychiatric comorbidity were five times more likely to be hospitalised than patients with a single psychiatric diagnosis. The most frequent psychiatric comorbidities involved substance use disorders (SUDs). CONCLUSIONS: Psychiatric disorders are underdiagnosed among ED patients. We believe that this underdiagnosis may be partly responsible for the high hospitalisation rates of ED patients with SUDs.

Adolescent↗
PubMed2005

The genome of the social amoeba Dictyostelium discoideum.

The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.

ATP-Binding Cassette Transporters↗
PubMed2004

In vitro and in vivo investigation of a novel monoclonal antibody to plasma cells (W5 mAb).

Natural antibodies (Abs), predominantly anti-Gal alpha 1-3Gal (Gal) Abs, in non-human primates and human beings present a major hurdle to successful pig-to-primate xenotransplantation. Attempts to inhibit anti-Gal Ab production in naïve baboons using non-specific immunosuppressive or B cell-specific reagents have failed. A new rat monoclonal antibody (W5 mAb) has been generated, which binds to all B cells, including memory cells, and to the majority of plasma cells, but not to T cells. It has been tested in vitro and in vivo. By immunoprecipitation, W5 mAb bound a human leukocyte antigen class II (HLA-DR) determinant. Sorting splenic or bone marrow W5+ cells resulted in a highly enriched anti-Gal Ab and total immunoglobulin (Ig)-secretory population. In vivo studies in baboons demonstrated that W5 mAb was safe but, despite the concomitant administration of an anti-CD154 mAb to inhibit sensitization, anti-rat Abs were detected within 10 days and inhibited the effect of the W5 mAb. High levels of W5 mAb were able to completely deplete B cells in the blood, but not in lymphoid tissues. Enzyme-linked spot-forming assay (ELISPOT) demonstrated that only 50 to 60% of secreting cells (SC) were depleted in the bone marrow. No reduction in the serum levels of anti-Gal Ab was observed. W5 mAb did not cause complete inhibition of anti-Gal Ab production, probably as a result of its inability to completely deplete B and plasma cells from all lymphoid compartments.

Animals↗
PubMed2003

An exploratory investigation of the effect of arsenic trioxide on anti-Gal antibody production in baboons.

BACKGROUND: Arsenic trioxide (As2O3) is an anticancer drug that has been reported to induce apoptosis and inhibit differentiation in human plasmacytoma and normal plasma/B cells without significant myelosuppression. We assessed the ability of As2O3 as single therapy or in combination with an anti-CD20 monoclonal antibody (mAb) and whole body irradiation (WBI) to deplete B and plasma cells, both in vitro and in vivo, and to reduce the level of anti-alphaGal1-3Gal antibody (anti-Gal Ab) in baboons. METHODS: In vitro the effect of As2O3 on antibody secretion (anti-Gal IgM, total IgG and IgM) was measured by enzyme-linked immunospot assay (ELISPOT). Its inhibition of proliferation of baboon splenocytes and the NCI-H929 human plasmacytoma cell line was measured by tritiated thymidine uptake. In vivo: all baboons (n=7) had undergone splenectomy. The effects of As2O3 (0.18 to 0.36 mg/kg) on B/plasma cell depletion and anti-Gal Ab production were assessed in three baboons. For comparison, three baboons received either WBI (2 x 150 cGy) or anti-CD20 mAb (20 mg/kg x 4 doses), or both WBI and anti-CD20 mAb. A final baboon received As2O3 + WBI (150 cGy) + anti-CD20 mAb. Anti-Gal Ab levels were measured daily by ELISA. Depletion of B cells from blood and bone marrow (BM) was monitored by flow cytometry and by histology of lymph nodes (LN). Autopsy was performed in three baboons. RESULTS: In vitro: As2O3 (at 5 x 10-6 mol/l) reduced anti-Gal IgM and total IgM secretors by 76% (P=0.53) and 95% (P < 0.001), respectively, but did not reduce total IgG secretors. As2O3 inhibited in a dose-dependent manner the proliferation of activated splenocytes and of the NCI-H929 plasmacytoma cell line; complete inhibition was achieved at a dose of 1 x 10-5 mol/l. In vivo: As2O3 was found to be toxic at the doses given and was associated with the deaths of two of the four baboons that received it. Daily intravenous therapy with As2O3 alone reduced B cells (CD20+) in the blood (by 50 to 90%), BM (40%) and LN (20 to 30%), but anti-Gal Ab levels were not significantly decreased. Anti-CD20 mAb therapy alone or WBI alone depleted B cells by 100% in the blood and BM, and 80 to 100% in the LN. The combination of anti-CD20 mAb + WBI led to depletion of B cells in blood, BM and LN for 3 months, but reduction of anti-Gal Ab remained marginal. The combination of As2O3 + anti-CD20 mAb + WBI did not reduce anti-Gal Ab levels further. At autopsy in the latter baboon, B cells remained present in Peyer's patches and tonsils. CONCLUSIONS: In vitro: As2O3 reduced B/plasma cell numbers and suppressed IgM secretors, but not IgG secretors. In vivo: As2O3 was not as effective as either anti-CD20 mAb or WBI in depleting B/plasma cells, and was largely ineffective in reducing anti-Gal Ab levels. Its administration was associated with considerable toxicity. Autopsy in one baboon suggested that B cells in Peyer's patches and tonsils may be resistant to therapy and remain a source of continuing production of anti-Gal Ab.

Animals↗
PubMed2002

Sequence of Plasmodium falciparum chromosomes 1, 3-9 and 13.

Since the sequencing of the first two chromosomes of the malaria parasite, Plasmodium falciparum, there has been a concerted effort to sequence and assemble the entire genome of this organism. Here we report the sequence of chromosomes 1, 3-9 and 13 of P. falciparum clone 3D7--these chromosomes account for approximately 55% of the total genome. We describe the methods used to map, sequence and annotate these chromosomes. By comparing our assemblies with the optical map, we indicate the completeness of the resulting sequence. During annotation, we assign Gene Ontology terms to the predicted gene products, and observe clustering of some malaria-specific terms to specific chromosomes. We identify a highly conserved sequence element found in the intergenic region of internal var genes that is not associated with their telomeric counterparts.

Animals↗
PubMed2002

Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2).

Streptomyces coelicolor is a representative of the group of soil-dwelling, filamentous bacteria responsible for producing most natural antibiotics used in human and veterinary medicine. Here we report the 8,667,507 base pair linear chromosome of this organism, containing the largest number of genes so far discovered in a bacterium. The 7,825 predicted genes include more than 20 clusters coding for known or predicted secondary metabolites. The genome contains an unprecedented proportion of regulatory genes, predominantly those likely to be involved in responses to external stimuli and stresses, and many duplicated gene sets that may represent 'tissue-specific' isoforms operating in different phases of colonial development, a unique situation for a bacterium. An ancient synteny was revealed between the central 'core' of the chromosome and the whole chromosome of pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae. The genome sequence will greatly increase our understanding of microbial life in the soil as well as aiding the generation of new drug candidates by genetic engineering.

Bacterial Proteins↗
PubMed2002

Pig hematopoietic cell chimerism in baboons conditioned with a nonmyeloablative regimen and CD154 blockade.

BACKGROUND: In an attempt to induce mixed hematopoietic chimerism and transplantation tolerance in the pig-to-primate model, we have infused high-dose porcine peripheral blood progenitor cells (PBPC) into baboons pretreated with a nonmyeloablative regimen and anti-CD154 monoclonal antibody (mAb). METHODS: Group 1 baboons (n=2) received a nonmyeloablative regimen including whole body irradiation, pharmacological immunosuppression, porcine hematopoietic growth factors, and immunoadsorption of anti-Galalpha1,3Gal (Gal) antibody before infusion of high doses of PBPC (2.7-4.6x10(10) cells/kg). In group 2 (n=5), cyclosporine was replaced by anti-CD154 mAb. Group 3 (n=3) received the group 1 regimen plus anti-CD154 mAb. RESULTS: In group 1, pig chimerism was detected in the blood by flow cytometry (FACS) for 5 days (with a maximum of 14%), and continuously up to 13 days by polymerase chain reaction (PCR). In group 2, pig chimerism was detectable for 5 days by FACS (maximum 33%) and continuously up to 28 days by PCR. In group 3, initial pig chimerism was detectable for 5 days by FACS (maximum 73%). Two of three baboons showed reappearance of pig cells on days 11 and 16, respectively. In one, in which no anti-Gal IgG could be detected for 30 days, pig cells were documented in the blood by FACS on days 16-22 (maximum 6% on day 19) and pig colony-forming cells were present in the blood on days 19-33, which we interpreted as evidence of engraftment. Microchimerism was continuous by PCR up to 33 days. CONCLUSIONS: These results suggest that there is no absolute barrier to pig hematopoietic cell engraftment in primates, and that this may be facilitated if the return of anti-Gal IgG can be prevented.

Animals↗
PubMed2002

Differential expression of Galalpha1,3Gal epitopes on fetal and adult porcine hematopoietic cells.

Galalpha1-3Gal (Gal) is the major epitope on pig tissues bound by human natural antibodies. Xenogeneic hematopoietic cell transplantation is being investigated to induce immunological tolerance to xenografts. We have investigated the level of Gal expression on pig hematopoietic cells. Cells were collected from pig fetal liver and bone marrow (BM), and also from adult BM and peripheral blood, before and after treatment with pig-specific hematopoietic growth factors. Fluorescent activated cell sorting (FACS) analysis was performed with the M86 monoclonal antibody (specific for Gal), lineage markers, and biotinylated stem cell factor (SCF) to detect c-kit expression. In fetal pig BM and liver, there was no significant difference in Gal expression between monocytes/macrophages (myeloid cells) and lymphocytes. In adult hematopoietic cells from all sources, Gal-positive subpopulations in T cells showed weak expression of Gal, whereas B cells demonstrated higher expression, and myeloid cells showed highest expression. Adult BM and mobilized peripheral blood progenitor cells contained small populations with very low or negligible expression of Gal. A very small population of c-kit-positive cells, indicating progenitor cells, were Gal-negative. The small Gal-negative population that exists in progenitor cells might explain why some pig colony forming units (CFU) can be resistant to human serum.

Animals↗
PubMed2001

Clearance of mobilized porcine peripheral blood progenitor cells is delayed by depletion of the phagocytic reticuloendothelial system in baboons.

INTRODUCTION: Attempts to achieve immunological tolerance to porcine tissues in nonhuman primates through establishment of mixed hematopoietic chimerism are hindered by the rapid clearance of mobilized porcine leukocytes, containing progenitor cells (pPBPCs), from the circulation. Eighteen hours after infusing 1-2 x 10(10) pPBPC/kg into baboons that had been depleted of circulating anti-alphaGal and complement, these cells are almost undetectable by flow cytometry. The aim of the present study was to identify mechanisms that contribute to rapid clearance of pPBPCs in the baboon. This was achieved by depleting, or blocking the Fc-receptors of, cells of the phagocytic reticuloendothelial system (RES) using medronate liposomes (MLs) or intravenous immunoglobulin (IVIg), respectively. METHODS: Baboons (preliminary studies, n=4) were used in a dose-finding and toxicity study to assess the effect of MLs on macrophage depletion in vivo. In another study, baboons (n=9) received a nonmyeloablative conditioning regimen (NMCR) aimed at inducing immunological tolerance, including splenectomy, whole body irradiation (300 cGy) or cyclophosphamide (80 mg/kg), thymic irradiation (700 cGy), T-cell depletion, complement depletion with cobra venom factor, mycophenolate mofetil, anti-CD154 monoclonal antibody, and multiple extracorporeal immunoadsorptions of anti-alphaGal antibodies. The baboons were divided into three groups: Group 1 (n=5) NMCR+pPBPC transplantation; Group 2 (n=2) NMCR+ML+pPBPC transplantation; and Group 3 (n=2) NMCR+IVIg+pPBPC transplantation. Detection of pig cells in the blood was assessed by fluorescence-activated cell sorter and polymerase chain reaction (PCR). RESULTS PRELIMINARY STUDIES: ML effectively depleted macrophages from the circulation in a dose-dependent manner. Group 1: On average, 14% pig cells were detected 2 hr postinfusion of 1 x 10(10) pPBPC/kg. After 18 hr, there were generally less than 1.5% pig cells detectable. Group 2: Substantially higher levels of pig cell chimerism (55-78%) were detected 2 hr postinfusion, even when a smaller number (0.5-1 x 10(10)/kg) of pPBPCs had been infused, and these levels were better sustained 18 hr later (10-52%). Group 3: In one baboon, 4.4% pig cells were detected 2 hr after infusion of 1 x 10(10) pPBPC/kg. After 18 hr, however, 7.4% pig cells were detected. A second baboon died 2 hr after infusion of 4 x 10(10) pPBPC/kg, with a total white blood cell count of 90,000, of which 70% were pig cells. No differences in microchimerism could be detected between the groups as determined by PCR. CONCLUSIONS: This is the first study to report an efficient decrease of phagocytic function by depletion of macrophages with MLs in a large-animal model. Depletion of macrophages with MLs led to initial higher chimerism and prolonged the survival of circulating pig cells in baboons. Blockade of macrophage function with IVIg had a more modest effect. Cells of the RES, therefore, play a major role in clearing pPBPCs from the circulation in baboons. Depletion or blockade of the RES may contribute to achieving mixed hematopoietic chimerism and induction of tolerance to a discordant xenograft.

Animals↗
PubMed2001

Mechanisms of thrombotic microangiopathy following xenogeneic hematopoietic progenitor cell transplantation.

INTRODUCTION: Attempts to induce tolerance though mixed hematopoietic chimerism in the discordant pig-to-baboon xenotransplantation model are sometimes complicated by a potentially fatal thrombotic microangiopathy in the recipient baboons. This state develops immediately after the infusion of porcine mobilized peripheral blood leukocytes, containing progenitor cells (PBPC). In our study, we examined the interaction of infused porcine PBPC with recipient platelets in vivo in baboons and investigated the underlying mechanisms using an in vitro model. METHODS: Two naïve baboons and six baboons preconditioned with irradiation and immunosuppression that received porcine PBPC were evaluated in vivo. The interaction of porcine and baboon PBPC with baboon platelets was investigated by an in vitro platelet aggregation assay. Fresh and cryopreserved PBPC were evaluated as well as PBPC obtained from growth-factor mobilized and unmobilized pigs. Furthermore, cellular subsets of PBPC were assessed for potential to induce platelet aggregation. Immunohistochemical staining was performed on platelet-leukocyte aggregates and potential inhibition of aggregation with anti-P-selectin and anti-CD154 mAbs, or eptifibatide (a GPIIb/IIIa receptor antagonist), was tested. RESULTS: All baboons that received porcine PBPC rapidly developed marked thrombocytopenia (<20,000/microl), elevated serum lactate dehydrogenase (>1,500U/liter), schistocytosis, and platelet aggregates on blood smear. Three baboons died (two untreated and one preconditioned), and substantive platelet aggregates containing porcine leukocytes were observed in the microvasculature of lungs and kidneys. In vitro, porcine, but not baboon, PBPC induced aggregation of baboon platelets in a dose-dependent manner. Immunohistological examination of these aggregates confirmed the incorporation of porcine leukocytes. Cryopreserved PBPC caused less aggregation than fresh PBPC, and growth-factor-mobilized PBPC induced less aggregation than unmobilized PBPC. Aggregation was fully abrogated by the addition of eptifibatide, and modulated by anti-P-selectin and anti-CD154 monoclonal antibodies that recognize adhesion receptors on activated platelets. Purified fractions (granulocytes, CD2+, and CD- cells) of porcine PBPC did not initiate aggregation, whereas addition of exogenous porcine PBPC membranes (erythrocytes, dead cells, and/or platelets) to the purified fractions exacerbated the aggregation response. CONCLUSIONS: These data indicate that porcine PBPC mediate aggregation of baboon platelets. This process likely contributes to the thrombotic microangiopathy observed after PBPC transplantation in the pig-to-baboon model. Eptifibatide can fully abrogate platelet aggregation induced by porcine PBPC in vitro. Purification of the progenitor cells from porcine PBPC and/or treatment of baboons with eptifibatide may be beneficial.

Animals↗
PubMed2001

Effects of specific anti-B and/or anti-plasma cell immunotherapy on antibody production in baboons: depletion of CD20- and CD22-positive B cells does not result in significantly decreased production of anti-alphaGal antibody.

Anti-Galalpha1-3Gal antibodies (antialphaGal Ab) are a major barrier to clinical xenotransplantation as they are believed to initiate both hyperacute and acute humoral rejection. Extracorporeal immunoadsorption (EIA) with alphaGal oligosaccharide columns temporarily depletes antialphaGal Ab, but their return is ultimately associated with graft destruction. We therefore assessed the ability of two immunotoxins (IT) and two monoclonal antibodies (mAb) to deplete B and/or plasma cells both in vitro and in vivo in baboons, and to observe the rate of return of antialphaGal Ab following EIA. The effects of the mouse anti-human IT anti-CD22-ricin A (proportional to CD22-IT, directed against a B cell determinant) and anti-CD38-ricin A (proportional to CD38-IT, B and plasma cell determinant) and the mouse anti-human anti-CD38 mAb (proportional to CD38 mAb) and mouse/human chimeric anti-human anti-CD20 mAb (proportional to CD20 mAb, Rituximab, B cell determinant) on B and plasma cell depletion and antialphaGal Ab production were assessed both in vitro and in vivo in baboons (n = 9) that had previously undergone splenectomy. For comparison, two baboons received nonmyeloablative whole body irradiation (WBI) (300 cGy), and one received myeloablative WBI (900 cGy). Depletion of B cells was monitored by flow cytometry of blood, bone marrow (BM) and lymph nodes (LN), staining with anti-CD20 and/or anti-CD22 mAbs, and by histology of LN. EIA was carried out after the therapy and antialphaGal Ab levels were measured daily. In vitro proportional to CD22-IT inhibited protein synthesis in the human Daudi B cell line more effectively than proportional to CD38-IT. Upon differentiation of B cells into plasma cells, however, less inhibition of protein synthesis after proportional to CD22-IT treatment was observed. Depleting CD20-positive cells in vitro from a baboon spleen cell population already depleted of granulocytes, monocytes, and T cells led to a relative enrichment of CD20-negative cells, that is plasma cells, and consequently resulted in a significant increase in antialphaGal Ab production by the remaining cells, whereas depleting CD38-positive cells resulted in a significant decrease in antialphaGal Ab production. In vivo, WBI (300 or 900 cGy) resulted in 100% B cell depletion in blood and BM, > 80% depletion in LN, with substantial recovery of B cells after 21 days and only transient reduction in antialphaGal Ab after EIA. Proportional to CD22-IT depleted B cells by > 97% in blood and BM, and by 60% in LN, but a rebound of B cells was observed after 14 and 62 days in LN and blood, respectively. At 7 days, serum antialphaGal IgG and IgM Ab levels were reduced by a maximum of 40-45% followed by a rebound to levels up to 12-fold that of baseline antialphaGal Ab by day 83 in one baboon. The results obtained with proportional to CD38-IT were inconclusive. This may have been, in part, due to inadequate conjugation of the toxin. Cell coating was 100% with proportional to CD38 mAb, but no changes in antialphaGal Ab production were observed. Proportional to CD20 mAb resulted in 100% depletion of B cells in blood and BM, and 80% in LN, with recovery of B cells starting at day 42. Adding 150cGy WBI at this time led to 100% depletion of B cells in the BM and LN. Although B cell depletion in blood and BM persisted for > 3 months, the reduction of serum antialphaGal IgG or IgM Ab levels was not sustained beyond 2 days. Proportional to CD20 mAb + WBI totally and efficiently depleted CD20- and CD22-positive B cells in blood, BM, and LN for > 3 months in vivo, but there was no sustained clinically significant reduction in serum antialphaGal Ab. The majority of antibody secretors are CD38-positive cells, but targeting these cells in vitro or in vivo with proportional to CD38-IT was not very effective. These observations suggest that CD20-and CD22-positive B cells are not the major source of antialphaGal Ab production. Future efforts will be directed towards suppression of plasma cell function.

Animals↗
PubMed2001

The prevalence of prophylaxis for deep vein thrombosis in acute hospital trusts.

OBJECTIVE: The effectiveness of activities to promote routine prophylaxis to prevent thromboembolism is difficult to assess because information about the prevalence of prophylaxis is sparse. The aim of this study was to assess the prevalence of deep vein thrombosis (DVT) prophylaxis for patients at risk in general medicine, general surgery, orthopaedics and gynaecology in Scotland and the North of England. DESIGN: Retrospective case note review of a random sample of episodes of care in a stratified random sample of directorates in Scotland and a convenience sample in England. SETTING: Twenty acute hospital directorates in Scotland and eight in the North of England. PARTICIPANTS: Case notes of patients at risk of thrombosis and discharged from the selected directorates in a 12-month period (n = 742). MAIN OUTCOME MEASURES: The proportion of patients receiving prophylaxis in each directorate. RESULTS: Overall, 469/526 (89%) of patients in Scotland and 199/216 (92%) in England received prophylaxis. The proportion varied from 71% in general medicine to 100% in orthopaedics. The frequency of use of different forms of prophylaxis varied between directorates. Approximately 60% of the patients who received prophylaxis received more than one form. CONCLUSIONS: Prophylaxis for DVT is well established for procedures and conditions that are known to increase the risk of thrombosis and for which there are no contraindications. Additional efforts to promote prophylaxis for these conditions are unlikely to be cost effective. Further research is needed to establish whether rates are equally high in other conditions, and whether the high prophylaxis rates are due to clinical effectiveness initiatives.

Anticoagulants↗
PubMed2000

Up-regulation of the parathyroid calcium-sensing receptor after burn injury in sheep: a potential contributory factor to postburn hypocalcemia.

OBJECTIVE: To test the hypothesis that the hypocalcemia and hypoparathyroidism that follow severe burn injury are related to up-regulation of the parathyroid gland calcium-sensing receptor (CaR), which may reduce the set-point for suppression of circulating parathyroid hormone by blood calcium. DESIGN: A controlled but unblinded study. SETTING: An investigational intensive care unit. SUBJECTS: Female range ewes. INTERVENTION: Sheep were subjected to a 40% total body surface area burn under anesthesia (n = 9) or sham burn receiving anesthesia and fluid resuscitation only (n = 8) and were killed 48 hrs postburn. MEASUREMENTS AND RESULTS: Blood ionized calcium, magnesium, and creatinine, and urinary calcium, magnesium, and creatinine were monitored for 48 hrs. After the sheep were killed, parathyroids (burn group, n = 3; sham group, n = 4) and kidneys (n = 4, each group) were harvested, snap frozen in liquid nitrogen, and analyzed for CaR messenger ribonucleic acid (mRNA) by Northern blot, and were analyzed for CaR cell-surface staining by immunocytochemistry with a polyclonal CaR-specific antiserum (parathyroids only). Bumed sheep were hypocalcemic and hypomagnesemic compared with sham-burned control sheep. CaR mRNA was increased by 50% (p < 0.005, analysis of variance) with a corresponding increase in the intensity of CaR immunoreactivity associated with the cell surface in parathyroids obtained from burned (n = 3) compared with sham-burned (n = 2) sheep. These findings are consistent with up-regulation of the parathyroid CaR and a related decrease in set-point for calcium suppression of parathyroid hormone secretion that may contribute to the previously reported postburn hypoparathyroidism and hypocalcemia.

Animals↗
PubMed2000

Image analysis for discrimination of cervical neoplasia.

Colposcopy involves visual imaging of the cervix for patients who have exhibited some prior indication of abnormality, and the major goals are to visually inspect for any malignancies and to guide biopsy sampling. Currently colposcopy equipment is being upgraded in many health care centers to incorporate digital image acquisition and archiving. These permanent images can be analyzed for characteristic features and color patterns which may enhance the specificity and objectivity of the routine exam. In this study a series of images from patients with biopsy confirmed cervical intraepithelia neoplasia stage 2/3 are compared with images from patients with biopsy confirmed immature squamous metaplasia, with the goal of determining optimal criteria for automated discrimination between them. All images were separated into their red, green, and blue channels, and comparisons were made between relative intensity, intensity variation, spatial frequencies, fractal dimension, and Euler number. This study indicates that computer-based processing of cervical images can provide some discrimination of the type of tissue features which are important for clinical evaluation, with the Euler number being the most clinically useful feature to discriminate metaplasia from neoplasia. Also there was a strong indication that morphology observed in the blue channel of the image provided more information about epithelial cell changes. Further research in this field can lead to advances in computer-aided diagnosis as well as the potential for online image enhancement in digital colposcopy.

Adolescent↗
PubMed1999

Core body temperature and sleep of older female insomniacs before and after passive body heating.

The purpose of this study was to investigate the relationship between core body temperature and sleep in older female insomniacs and changes in that relationship as a result of passive body heating (PBH). An increase in body temperature early in the evening by way of PBH in older female insomniacs increased SWS in the early part of the sleep period and improved sleep continuity. Fourteen older female insomniacs (60-73 years old) participated in at least two consecutive nights of PBH involving hot (40-40.5 degrees C) baths 1.5-2 hours before bedtime. Hot baths resulted in a significant delay in the phase of the core body temperature rhythm compared to baseline nights. This delay in temperature phase paralleled the improvements in sleep quality.

Adult↗
PubMed1999

Efficient and durable gene marking of hematopoietic progenitor cells in nonhuman primates after nonablative conditioning.

Optimization of mobilization, harvest, and transduction of hematopoietic stem cells is critical to successful stem cell gene therapy. We evaluated the utility of a novel protocol involving Flt3-ligand (Flt3-L) and granulocyte colony-stimulating factor (G-CSF) mobilization of peripheral blood stem cells and retrovirus transduction using hematopoietic growth factors to introduce a reporter gene, murine CD24 (mCD24), into hematopoietic stem cells in nonhuman primates. Rhesus macaques were treated with Flt3-L (200 microgram/kg) and G-CSF (20 microgram/kg) for 7 days and autologous CD34(+) peripheral blood stem cells harvested by leukapheresis. CD34(+) cells were transduced with an MFGS-based retrovirus vector encoding mCD24 using 4 daily transductions with centrifugations in the presence of Flt3-L (100 ng/mL), human stem cell factor (50 ng/mL), and PIXY321 (50 ng/mL) in serum-free medium. An important and novel feature of this study is that enhanced in vivo engraftment of transduced stem cells was achieved by conditioning the animals with a low-morbidity regimen of sublethal irradiation (320 to 400 cGy) on the day of transplantation. Engraftment was monitored sequentially in the bone marrow and blood using both multiparameter flow cytometry and semi-quantitative DNA polymerase chain reaction (PCR). Our data show successful and persistent engraftment of transduced primitive progenitors capable of giving rise to marked cells of multiple hematopoietic lineages, including granulocytes, monocytes, and B and T lymphocytes. At 4 to 6 weeks posttransplantation, 47% +/- 32% (n = 4) of granulocytes expressed mCD24 antigen at the cell surface. Peak in vivo levels of genetically modified peripheral blood lymphocytes approached 35% +/- 22% (n = 4) as assessed both by flow cytometry and PCR 6 to 10 weeks posttransplantation. In addition, naïve (CD45RA(+) and CD62L(+)) CD4(+) and CD8(+) cells were the predominant phenotype of the marked CD3(+) T cells detected at early time points. A high level of marking persisted at between 10% and 15% of peripheral blood leukocytes for 4 months and at lower levels past 6 months in some animals. A cytotoxic T-lymphocyte response against mCD24 was detected in only 1 animal. This degree of persistent long-lived, high-level gene marking of multiple hematopoietic lineages, including naïve T cells, using a nonablative marrow conditioning regimen represents an important step toward the ultimate goal of high-level permanent transduced gene expression in stem cells.

Animals↗