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Biomedical subjects

M Newman

Publications and source records attributed to M Newman.

At least 19 recordsLinked to original sources
PubMed2006

Alzheimer disease: amyloidogenesis, the presenilins and animal models.

Alzheimer's disease is the most prevalent form of dementia. Neuropathogenesis is proposed to be a result of the accumulation of amyloid beta peptides in the brain together with oxidative stress mechanisms and neuroinflammation. The presenilin proteins are central to the gamma-secretase cleavage of the amyloid prescursor protein (APP), releasing the amyloid beta peptide. Point mutations in the presenilin genes lead to cases of familial Alzheimer's disease by increasing APP cleavage resulting in excess amyloid beta formation. This review discusses the molecular mechanism of Alzheimer's disease with a focus on the presenilin genes. Alternative splicing of transcripts from these genes and how these may function in several disease states is discussed. There is an emphasis on the importance of animal models in elucidating the molecular mechanisms behind the development of Alzheimer's disease and how the zebrafish, Danio rerio, can be used as a model organism for analysis of presenilin function and Alzheimer's disease pathogenesis.

Alzheimer Disease↗
PubMed2006

Treadmill training for individuals with multiple sclerosis: a pilot randomised trial.

This pilot study investigated whether 4 weeks of aerobic treadmill training in individuals with multiple sclerosis (MS) improved mobility and reduced fatigue. Individuals with MS were recruited to this prospective, randomised controlled trial. Individuals were assessed at baseline, week 7 and 12 with a 10 metre timed walk, a 2 minute walk, the Rivermead Mobility Index, and the Fatigue Severity Scale. After a pre-assessment familiarisation session and a baseline assessment, individuals were randomly allocated to an initial intervention or delayed intervention group. Treadmill training consisted of 4 weeks of supervised aerobic exercise delivered weeks 3-6 in the immediate group and 8-11 in the delayed group. Of the initial 19 recruits, 16 individuals completed the study. There was a significant difference in walking endurance between the delayed and immediate groups at baseline (p<0.05). On reassessment in week 7, decreases in 10 metre walk time were found in both groups, which was significant in the immediate group (p<0.05). The 2 minute walk distance significantly increased in both groups (p<0.05). In the training group, reassessed at week 12 after training ceased, there was a return towards baseline scores. No significant changes in fatigue scores were found. This study showed that in individuals with MS, aerobic treadmill training is feasible and well tolerated. Walking speed and endurance increased following training with no increase in reported fatigue. Detraining occurred in the period following training. A larger randomised clinical trial is warranted.

Adult↗
PubMed2005

The usefulness of a single measurement of insulin-like growth factor-1 as a predictor of embryo yield and pregnancy rates in a bovine MOET program.

The objective was to determine if a single measurement of plasma insulin-like growth factor-1 (IGF-1) could predict the number of viable embryos obtained from donors and the likelihood of pregnancy in recipients in multiple ovulation and embryo transfer (MOET) programs in cattle. The embryo yields from 101 embryo recoveries were examined in maiden Holstein heifers (n=75) and multiparous Holstein cows (lactating cows n=20, dry cows n=6). Donors were super stimulated with FSH and embryo recovery was done non-surgically 7 days after artificial insemination. Embryos were classified according to the IETS criteria. Pregnancy rates in 100 maiden Holstein heifer recipients were analysed. Recipients were on day 7+/-1 of the estrous cycle at transfer. Pregnancy diagnosis was carried out at day 30 (PD 30) and rechecked at day 60 (PD 60) after transfer. Blood samples from coccygeal vessels taken at the time of embryo recovery (donors) and transfer (recipients) were analysed for IGF-1, insulin, beta-hydroxybutyrate (beta-OHB), non-esterified fatty acids (NEFA), urea and cholesterol. There was a negative correlation between the number of viable embryos and insulin (r=-0.33, P=0.025) in donor heifers. In donor cows, the number of viable embryos was correlated with IGF-1 (r=0.43, P=0.028) and cholesterol (r=-0.43, P=0.027). In recipients, PD30 and PD 60 were not affected by any of the circulating parameters analysed. Insulin, IGF-1 and cholesterol only explained 8.9, 13.9 and 15.8% of the variation in the production of viable embryos, respectively. Several factors affect MOET programs and under the circumstances of the present study the usefulness of hormonal and metabolic profiles as predictors of the outcome of this biotechnology was limited.

3-Hydroxybutyric Acid↗
PubMed2005

Cisplatin and gemcitabine induction chemotherapy followed by concurrent chemoradiotherapy or surgery for locally advanced non-small cell lung cancer.

BACKGROUND: We report a study of induction chemotherapy followed by concurrent chemoradiotherapy for stage IIIA/IIIB non-small cell lung cancer. METHODS: Patients received two cycles of induction chemotherapy with cisplatin 100 mg/m(2) on day 1 and gemcitabine 1000 mg/m(2) on days 1, 8, and 15 of a 28-day cycle. If the disease was resectable [corrected] surgery was followed with two further cycles. If unresectable, patients received cisplatin 100 mg/m(2) day 1, 29 with 5-fluorouracil 1000 mg/m(2) per 24 h continuous infusion for 96 h on days 2-5 and days 30-33 of the radiotherapy administration. Radiation therapy consisted of 63 Gy, 35 fractions, 7 weeks. RESULTS: Of 48 patients, 40% had a partial response to induction chemotherapy. Four of eleven patients with stage IIIA tumours had resectable disease. The remaining seven patients plus 37 with stage IIIB disease had chemoradiotherapy. Response at the completion of all therapy was 62% (IIIA 73%, IIIB 59%). For all patients the median survival was 15.3 months: 1 year and 3 years, 58% and 25%, respectively. Those with IIIB disease responding to induction chemotherapy had significantly superior survival to those that did not respond (37 months vs 11 months; P = 0.005). This remained significant from a landmark at 8 weeks after the start of treatment (P = 0.01). CONCLUSION: These results are equivalent to other studies using induction chemotherapy prior to concurrent chemoradiotherapy. Response to induction chemotherapy may have major prognostic significance.

Adult↗
PubMed2004

Over-expression of anti-CD75 reactive proteins on distal and collecting renal tubular epithelial cells in calcium-oxalate stone-forming kidneys in Egypt.

OBJECTIVE: To assess the nature, distribution and expression pattern of CD75, a neuraminidase-sensitive lymphocyte cell surface differentiation antigen, in calcium oxalate (CaOx) stone disease, as cell-surface sialic acid might be involved CaOx crystal binding, and lectin-binding assays suggest that sialic acid in the alpha2,6 position is upregulated in stone-forming kidneys. MATERIALS AND METHODS: Human CaOx stone-forming and normal kidneys (13 each) and primary kidney epithelial cells (CAKI-1, three samples) were analysed. The protein pattern, distribution and expression of CD75 were analysed using Western blotting, immunohistology and semi-quantitative confocal laser scanning microscopy (cLSM). Production was investigated by alpha2,6-sialyltransferase specific reverse transcription-polymerase chain reaction. RESULTS: Western blotting showed one strong band at approximately 43 kDa that reacted with anti-CD75 when renal epithelial and CAKI-1 tumour cell extracts were analysed. However, in renal tissue extracts of CaOx stone formers there were additional bands at 120 and 205 kDa. Image processing after cLSM showed that anti-CD75 reactivity was significantly greater on E-cadherin-positive distal and collecting tubular cells from CaOx stone-forming kidneys, at a mean (sd) intensity of 87 (7), than on those from normal kidneys, at 41 (5) (P = 0.005). CONCLUSION: CD75 expression in human kidney was primarily on the luminal surface of distal tubules and collecting ducts. Whether increased epithelial CD75 expression in CaOx stone disease is a cause or result of the disease remains to be clarified.

Antigens, CD↗
PubMed2002

Optimizing vaccine design for cellular processing, MHC binding and TCR recognition.

In this review we describe the methods and processes that our group have developed while aiming to test and design multiepitope vaccines for infectious diseases and cancer. Testing the performance of vaccines composed of epitopes restricted by human leukocyte antigen (HLA) molecules is accomplished by in vitro antigenicity assays, as well as in vivo immunogenicity assays in HLA transgenics. The efficiency by which multiepitope vaccines are processed is optimized by spacer residues, which are designed to facilitate generation by natural processing of the various class I- and class II-restricted epitopes. Methods and strategies to test and optimize HLA binding affinity, patient coverage from the vaccine construct, and TCR recognition of HLA/epitope complexes are also discussed.

Epitopes↗
PubMed2001

Optimization of epitope processing enhances immunogenicity of multiepitope DNA vaccines.

Experimental DNA vaccines comprised of multiple minimal cytotoxic T lymphocytes (CTL) epitopes can effectively induce broad CTL responses; however, such constructs frequently exhibit significant variation in epitope immunogenicity. Antigenicity assays utilizing human cells transfected with one such multiepitope construct revealed that the epitopes with poor immunogenicity were inefficiently processed in transfected cells. Compilation of a database of 94 epitope/flanking region combinations, for which immunogenicity was measured experimentally, revealed that the type of residue immediately following the carboxyl-terminus of the epitope exerted a prominent effect on immunogenicity. Experiments utilizing a variety of HBV-specific vaccine constructs demonstrated epitope immunogenicity could be modulated by the insertion of a single amino acid and the effect on immunogenicity could be ascribed to modulation of processing efficiency. These findings demonstrate that multiepitope DNA vaccines can be engineered to enhance CTL immunogenicity by increasing processing efficiency.

AIDS Vaccines↗
PubMed2001

Prevalence and correlates of anemia in a large cohort of HIV-infected women: Women's Interagency HIV Study.

Anemia is a common manifestation of HIV infection, occurring in approximately 30% of patients with asymptomatic infection and in as many as 75% to 80% of those with AIDS. Anemia has been associated with decreased quality of life and decreased survival. We performed a cross-sectional study nested within a multicenter prospective cohort study to describe the prevalence of anemia in 2056 HIV-infected and 569 HIV-negative women as well as to define the demographic, clinical, immunologic, and virologic correlates of anemia among HIV-infected women. A total of 37% of HIV-positive women and 17% of HIV-negative women had hemoglobin levels < 12 g/dl (p < .001). Factors associated with anemia in HIV-positive and HIV-negative women included mean corpuscular volume (MCV) < 80 fl (p < .001) and black race (p < .001). Among HIV-infected women, multivariate logistic analyses revealed that African American race (p < .0001), MCV < 80 fl (p < .0001), CD4 count < 200 per microliter (p <.0001), higher HIV RNA in plasma (p = .02), current use of ZDV (p = .01), and history of clinical AIDS (p = .004) were all independent predictors of anemia. These data indicate that worsening parameters of HIV disease are associated with anemia among HIV-infected women. Black women and women with low MCV values are at increased risk for anemia independent of HIV status.

Adolescent↗
PubMed2001

Argyria in the ED.

Explore the source record for details and available documents.

Administration, Oral↗
PubMed2001

Identification of novel HLA-A2-restricted human immunodeficiency virus type 1-specific cytotoxic T-lymphocyte epitopes predicted by the HLA-A2 supertype peptide-binding motif.

Virus-specific cytotoxic T-lymphocyte (CTL) responses are critical in the control of human immunodeficiency virus type 1 (HIV-1) infection and will play an important part in therapeutic and prophylactic HIV-1 vaccines. The identification of virus-specific epitopes that are efficiently recognized by CTL is the first step in the development of future vaccines. Here we describe the immunological characterization of a number of novel HIV-1-specific, HLA-A2-restricted CTL epitopes that share a high degree of conservation within HIV-1 and a strong binding to different alleles of the HLA-A2 superfamily. These novel epitopes include the first reported CTL epitope in the Vpr protein. Two of the novel epitopes were immunodominant among the HLA-A2-restricted CTL responses of individuals with acute and chronic HIV-1 infection. The novel CTL epitopes identified here should be included in future vaccines designed to induce HIV-1-specific CTL responses restricted by the HLA-A2 superfamily and will be important to assess in immunogenicity studies in infected persons and in uninfected recipients of candidate HIV-1 vaccines.

Acquired Immunodeficiency Syndrome↗
PubMed2001

LY 294002, an inhibitor of phosphatidylinositol 3-kinase, inhibits GH-mediated expression of the IGF-I gene in rat hepatocytes.

The signal transduction pathways that mediate GH-dependent regulation of IGF-I gene expression remain poorly defined. To establish a GH-responsive in vitro model system to study the effect of GH on the expression of the endogenous IGF-I gene, primary hepatocytes from adult male rats were prepared. These cells expressed both the GH receptor and the IGF-I gene, as demonstrated using a ribonuclease protection assay. Western blot analyses using antibodies directed against the phosphorylated forms of the ERKs, signal transducer and activator of transcription-5, and Akt/protein kinase B, a protein kinase that is downstream of PI3K, demonstrated GH-dependent phosphorylation of these signaling molecules. These signaling molecules are components of the major signal transduction pathways that are activated by GH. To determine whether GH-responsive IGF-I gene expression could be demonstrated in these cells, hepatocytes were treated without or with 50 ng/ml GH for 3--48 h. IGF-I mRNA levels increased within 3 h, and a maximal 2.2-fold increase was observed after 24 h of GH treatment. To determine whether ERK activation contributes to GH-induced IGF-I gene expression, hepatocytes were treated for 12 h without or with 50 ng/ml GH and 50 microM PD98059, an inhibitor of MAPK kinase-1 and -2. Treatment with PD98059 did not have a significant effect on GH-induced IGF-I gene expression. Similar studies were performed using 50 microM LY 294002, an inhibitor of PI3K. These studies demonstrated that treatment with LY 294002 completely abrogated GH-induced IGF-I gene expression. In contrast, PI3K-specific doses of another inhibitor of PI3K, wortmannin, failed to inhibit the GH-induced increase in IGF-I mRNA levels. In summary, rat hepatocytes in primary culture provide a good model system to study GH-induced IGF-I gene expression, and the results of these studies suggest that a signaling pathway inhibited by LY 294002, possibly a PI3K-dependent pathway, is important for GH-stimulated IGF-I gene expression in hepatocytes.

Animals↗