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Biomedical subjects

A Miller

Publications and source records attributed to A Miller.

At least 145 records · Page 8Linked to original sources
PubMed1999

Appropriateness of psychostimulant prescription to children: theoretical and empirical perspectives.

OBJECTIVES: 1) To consider study designs for evaluating how appropriately stimulant medications are prescribed to children. 2) To investigate appropriateness by seeking evidence of consensus around how stimulant management should be undertaken, collecting and reviewing evidence of actual physician practice in relation to use of stimulants, and evaluating the closeness of fit between recommended and actual practice. METHOD: Electronic databases and other published and unpublished material were searched for the decade 1987-1997 to identify 1) authoritative recommendations for medical management of attention-deficit hyperactivity disorder (ADHD) and 2) surveys of physician practice. Available information was analyzed qualitatively for commonalities and trends and for concordance between recommendations and practice. RESULTS: Despite differences in emphasis between experts, common themes were identifiable regarding prerequisites and follow-up for use of stimulants. Overall, it was rare to find physician practice in accordance with expert recommendations more than 70% of the time, suggesting that management may be suboptimal in at least 30% of children treated with medication for ADHD. Across surveys, consistent differences appear in physician practice patterns related to practice type. Management by specialist consultants approximates standards recommended by experts, while management by primary care practitioners diverges from these standards. CONCLUSIONS: There are grounds for concern about the quality and appropriateness of medical management for children with ADHD. The methodology used in this study holds promise for wider application, with planning and refinement. There is a need to find ways to improve care for children with ADHD provided by primary care physicians.

Attention Deficit Disorder with Hyperactivity↗
PubMed1999

Treating inflammatory bowel disease during pregnancy: risks and safety of drug therapy.

The safety of drug therapy for inflammatory bowel disease during pregnancy is an important clinical concern. Current available information is largely derived from animal studies and clinical experience among patients with inflammatory bowel disease and autoimmune disorders and organ transplant recipients. However, these data are confounded by various factors including difficulty projecting the results of animal studies to humans, methodological deficiencies of some studies, insufficient experience with certain agents, difficulty distinguishing the fetal effects of underlying disease from drug therapy and a need to consider the impact of background rates of adverse fetal outcomes which apply to all pregnancies. In inflammatory bowel disease, the effects of active inflammation on the fetus are believed to be more harmful than those of drug treatment, and therapy is often justified to induce or maintain remission during pregnancy. The choice of appropriate treatment is determined by the severity of the disease and the potential for drug toxicity. No causal relationship has been established between exposure to sulfasalazine or other 5-aminosalicylic acid drugs and the development of congenital malformations. These drugs may be used with relative safety during pregnancy and lactation. Considerable experience with corticosteroids have shown them to pose very small risk to the developing fetus. Current evidence indicates that maternal use of azathioprine is not associated with an increased risk of congenital malformations, though impaired fetal immunity, growth retardation or prematurity is occasionally observed. Preliminary evidence derived from patients with inflammatory bowel disease show no significant fetal toxicity following first trimester exposure to mercaptopurine, though its elective use in pregnancy is controversial. Cyclosporin is not teratogenic, but may be associated with growth retardation and prematurity. Pregnancy should be avoided in women treated with methotrexate because of its known abortifacient effects and risk of causing typical malformations. Although treatment with metronidazole or ciprofloxacin for short durations appear to be devoid of adverse fetal reactions, the effect of prolonged exposure as required in Crohn's disease remains unknown.

Abnormalities, Drug-Induced↗
PubMed1999

Intravascular lymphomatosis. A report of ten patients with central nervous system involvement and a review of the disease process.

The clinical, radiographic, and pathological findings in ten cases of intravascular lymphomatosis with central nervous system involvement seen at our institution over a 15-year period are presented. Nine patients presented with a subacute, progressive multifocal neurologic disorder. Most patients had fever, anemia, and elevation of the erythrocyte sedimentation rate. As the illness evolved, computerized tomography scanning and magnetic resonance imaging showed evidence of multifocal central nervous system disease. Angiography was nondiagnostic but suggested vasculitis in six cases. A response to empiric corticosteroid treatment was typical but usually transient. In six patients, the diagnosis was made antemortem by brain biopsy. The prognosis of patients was primarily dependent on early diagnosis and treatment, before massive central nervous system damage occurred. Treatment with chemotherapy, with or without radiotherapy, was associated with stabilization of the disease in three of five patients.

Aged↗
PubMed1998

Designing an effective counteradvertising campaign--Massachusetts.

In this report, the author reviews the major lessons from the Massachusetts tobacco counteradvertising efforts. Ms. Miller ties in the Massachusetts three-pronged campaign of youth prevention, adult cessation, and public support with focus group-tested counteradvertising strategies.

Adolescent↗
PubMed1998

Treatment of multiple sclerosis with copolymer-1 (Copaxone): implicating mechanisms of Th1 to Th2/Th3 immune-deviation.

The synthetic polypeptide copolymer-1 (Cop-1; Copaxone; Glatiramer Acetate) has been recently approved as an effective treatment in relapsing multiple sclerosis (MS). A large body of evidence demonstrates that Cop-1 induces active suppression of CNS-inflammatory disease in animal models. However, Cop-1-mediated suppressor mechanisms have not yet been elucidated in humans. A 12-month open study following clinical and immunological parameters of ten relapsing MS patients treated with Cop-1 is presented. Relapse rates and disability scores (EDSS) were evaluated prior to and after 12 months of treatment. The immunological parameters assessed prior to and at 3 months' interval during treatment included serum levels of soluble IL-2 receptor (sIL-2R) and IL-10 as well as leukocyte cytokine mRNA expression of TNF alpha, IL-4 and TGF-beta. Copaxone treatment was found to lead to a significant reduction in the mean annual relapse rate (from 1.4 prior to treatment to 0.6 during treatment) and stabilization of disability in 90% of the patients. The treatment was accompanied by an elevation of serum IL-10 levels, suppression of the pro-inflammatory cytokine TNF alpha mRNA, and an elevation of the anti-inflammatory cytokines TGF-beta and IL-4 mRNAs in PBLs. These results suggest that the beneficial clinical effects of Copaxone in MS patients may be attributed to changes in activation of T cell subsets and a shift from Th1 to Th2/Th3 cytokine profile, probably leading to Cop-1-driven mechanisms of bystander suppression.

Adult↗
PubMed1998

IL-17 stimulates granulopoiesis in mice: use of an alternate, novel gene therapy-derived method for in vivo evaluation of cytokines.

IL-17 is a novel cytokine secreted principally by CD4+ T cells. It has been shown to support the growth of hemopoietic progenitors in vitro; however, its in vivo effects are presently unknown. Adenovirus-mediated gene transfer of the murine IL-17 cDNA targeted to the liver (5 x 10(9) plaque-forming units (PFU) intravenous) resulted in a transiently transgenic phenotype, with dramatic effects on in vivo granulopoiesis. Initially, there was a significant increase (fivefold) in the peripheral white blood count (WBC), including a 10-fold rise in the absolute neutrophil count. This was associated with a doubling in the spleen size over 7-14 days after gene transfer, which returned to near baseline by day 21, although the white blood cell count remained elevated. There was a profound stimulation of splenic hemopoiesis as demonstrated by an increase in total cellularity by 50% 7 days after gene transfer and an increase in hemopoietic colony formation. A maximal increase in frequency of high proliferative potential colonies (HPPC) (11-fold) and CFU-granulocyte-macrophage (GM) and CFU-granulocyte-erythrocyte-megakaryocyte-monocyte (GEMM) (CFU) (6-fold) was seen on day 3 after IL-17 gene transfer. Both CFU and HPPC remained significantly elevated in the spleen throughout day 21, but at reduced levels compared with day 3. Bone marrow CFU and HPPC were elevated on day 3 only by 75% and 25%, respectively, without changes in total cellularity. Thus, murine IL-17 is a cytokine that can stimulate granulopoiesis in vivo. Since IL-17 is principally produced by CD4+ T cells, this cytokine could have therapeutic implications in AIDS-related bone marrow failure and opportunistic infections.

3T3 Cells↗
PubMed1998

Concurrent and predictive validity of the Allen Cognitive Levels Assessment.

The present study examined the concurrent and predictive validity of the Allen Cognitive Levels (ACL) Assessment in a sample of 110 medicated patients with schizophrenia who received the ACL at discharge from a state psychiatric facility. Subsamples within this group of patients had received an Activities of Daily Living assessment (n = 64) and a comprehensive neuropsychological test battery (n = 48) at discharge, or a battery of community follow-up measures (n = 30) 1-3.5 years following discharge as part of other investigations. Positive correlations were found between the ACL and concurrent measures of adaptive and cognitive function. With respect to cognitive variables, stepwise multiple regression analysis revealed that the majority of the variance in ACL scores was predicted by neuropsychological test scores assessing higher level cognitive processes, such as visual organization, manipulation of information in working memory, and ability to inhibit a response to a prepotent stimulus. Finally, results revealed positive relationships between the ACL obtained at discharge and community functioning at follow-up. The results of this study provide some evidence for the concurrent and predictive validity of the ACL for patients with schizophrenia and suggest that further study of this assessment tool would be important to pursue in future investigations.

Adult↗
PubMed1998

Synthetic signal peptides specifically recognize SecA and stimulate ATPase activity in the absence of preprotein.

Although it is known that virtually all exported proteins require a signal peptide, it is not clearly understood how the signal peptide interfaces with the translocation machinery to achieve transport. In this study we document a direct interaction between the signal peptide and SecA, a primary component of the translocase in Escherichia coli, and show that the signal peptide itself can stimulate SecA-lipid ATPase activity. Using synthetic signal peptides corresponding to the wild type alkaline phosphatase signal sequence and two model sequences, we find that the extent of stimulation of SecA ATPase activity by the different peptides parallels the hierarchy of results found for in vivo function (Izard, J. W., Doughty, M. B., and Kendall, D. A. (1995) Biochemistry 34, 9904-9912). The peptide-induced activity requires a lipid to protein molar ratio of at least 300:1 and liposomes enriched in negatively charged phospholipids. Furthermore, specific binding of the signal peptide to SecA was demonstrated using chemical cross-linking and competition with unlabeled peptides.

Adenosine Triphosphatases↗
PubMed1998

Role of nitric oxide and free radicals in the contractile response to non-preactivated leukocytes.

Previous studies from our laboratory have shown that nitric oxide (NO) can reduce the release of free radicals from activated leukocytes. The aim of this study was to assess the role of endothelium-derived nitric oxide and leukocyte-derived free radicals in the contractile response to non-preactivated leukocytes. Vessel tension studies were performed in rabbit endothelium-intact aortic vessel rings precontracted with 5-hydroxytryptamine (1 microM). Addition of leukocytes isolated from rabbit blood were added to the rings in increasing concentrations (10(3)-10(6) cell ml(-1)) under control conditions and in the presence of L-nitroarginine methyl ester (L-NAME 1 mM), D-NAME (1 mM), or superoxide dismutase (100 U ml(-1)). The responses to superoxide radical (generated by xanthine plus xanthine oxidase, X/XO), hydrogen peroxide, hypochlorite and peroxynitrite were also assessed. The nature of the free radicals released from non-activated isolated leukocytes, zymosan-stimulated leukocytes (in whole blood) and isolated vessel rings was assessed using luminol-enhanced chemiluminescence. Cumulative addition of leukocyte suspensions to aortic rings caused a concentration-dependent contractile response which was abolished by preincubation of the vessel ring with L-NAME. D-NAME and superoxide dismutase were without effect. All the free radicals tested produced a relaxation of the precontracted aortic ring. The response to X/XO was not affected by superoxide dismutase, but abolished by catalase. The responses to hydrogen peroxide and hypochlorite were both found to be dependent upon the presence of endothelium and NO. The response to peroxynitrite was endothelium-independent and was blocked by methylene blue. While the main free radical released from unstimulated leukocytes and vessel rings was superoxide, the main radical released from activated leukocytes was found to be hypochlorite. These results suggest that the vascular contraction seen in response to non-preactivated leukocytes is due to inhibition, by NO, of the release of free radicals from the leukocytes when activated by contact with the vascular endothelium, thus allowing co-released vasoconstrictor substances to exert their effect.

Animals↗
PubMed1998

E-cadherin germline mutations in familial gastric cancer.

The identification of genes predisposing to familial cancer is an essential step towards understanding the molecular events underlying tumorigenesis and is critical for the clinical management of affected families. Despite a declining incidence, gastric cancer remains a major cause of cancer death worldwide, and about 10% of cases show familial clustering. The relative contributions of inherited susceptibility and environmental effects to familial gastric cancer are poorly understood because little is known of the genetic events that predispose to gastric cancer. Here we describe the identification of the gene responsible for early-onset, histologically poorly differentiated, high grade, diffuse gastric cancer in a large kindred from New Zealand (Aotearoa). Genetic linkage analysis demonstrated significant linkage to markers flanking the gene for the calcium-dependent cell-adhesion protein E-cadherin. Sequencing of the E-cadherin gene revealed a G --> T nucleotide substitution in the donor splice consensus sequence of exon 7, leading to a truncated gene product. Diminished E-cadherin expression is associated with aggressive, poorly differentiated carcinomas. Underexpression of E-cadherin is a prognostic marker of poor clinical outcome in many tumour types, and restored expression of E-cadherin in tumour models can suppress the invasiveness of epithelial tumour cells. The role of E-cadherin in gastric cancer susceptibility was confirmed by identifying inactivating mutations in other gastric cancer families. In one family, a frameshift mutation was identified in exon 15, and in a second family a premature stop codon interrupted exon 13. These results describe, to our knowledge for the first time, a molecular basis for familial gastric cancer, and confirm the important role of E-cadherin mutations in cancer.

Adolescent↗
PubMed1998

Use of recombinant human erythropoietin for management of anemia in dogs and cats with renal failure.

OBJECTIVE: To test efficacy and safety of recombinant human erythropoietin (r-HuEPO) administration in dogs and cats with naturally developing chronic renal failure. DESIGN: Case series. ANIMALS: 6 client-owned dogs and 11 client-owned cats with chronic renal failure. PROCEDURES: r-HuEPO was administered intravenously or subcutaneously. Erythropoietic effects were monitored by determining CBC, performing cytologic examination of bone marrow aspirates, and measuring serum iron concentration before and during treatment. Development of adverse effects was monitored by performing sequential clinical assessments, CBC, and serum biochemical tests and by measuring indirect blood pressure and anti-r-HuEPO antibody titers. RESULTS: Administration of r-HuEPO increased RBC and reticulocyte counts, hemoglobin concentration, and Hct comparably in dogs and cats. Assessments of clinical well-being, including appetite, energy, weight gain, alertness, strength, and playfulness, were improved variably. Adverse effects, including anemia, anti-r-HuEPO antibody production, seizures, systemic hypertension, and iron deficiency, were demonstrated inconsistently in dogs and cats. CLINICAL IMPLICATIONS: Anemia contributes to clinical manifestations of chronic renal failure in dogs and cats. Administration of r-HuEPO has the potential to resolve anemia and improve clinical well-being. However, its administration poses risks of antibody production and adverse effects associated with correction of RBC mass. Use of r-HuEPO in dogs and cats requires conscientious assessment of risks and benefits until homologous forms of erythropoietin are available.

Anemia↗
PubMed1998

Molecular packing of type I collagen in tendon.

X-ray diffraction of rat tail tendon shows that type I collagen fibrils contain regions of three-dimensional crystalline arrays; where molecular packing is speculated to be by a staggered sheet or microfibril arrangement. The X-ray diffraction pattern also contains a significant amount of diffuse scatter indicative of static and thermal disorder in fibrils. Removal of the diffuse scatter from the equatorial region of X-ray diffraction patterns obtained using synchrotron radiation allowed the Bragg intensities to be viewed on a flat background. Indexing of Bragg peak intensity on the 10, -10, 0 -1, 01, -11 and 1-1 row-lines of the triclinic unit cell have been used here to test possible sheet and microfibril packing arrangements. The relative translation of molecular segments in the gap and overlap regions as well as the telopeptide orientation have been investigated. A global search through combinations of molecular packing and molecular translation revealed that the sheet-type conformations cannot account for the observed low-angle off-meridional Bragg peak intensity distribution. A superior fit is obtained with D-staggered left-handed microfibril structures. The orientation of the telopeptides may indicate that there are interconnections between microfibrils that may explain the difficulty in isolating individual microfibrillar structures.

Animals↗
PubMed1998

Food-bound B12 absorption and serum total homocysteine in patients with low serum B12 levels.

This study was undertaken to determine whether measurements of serum total homocysteine (Hcys) and bound B12 absorption are useful in determining which patients with low- or low-normal levels of serum B12 are B12 deficient. In 40 patients with low or borderline serum levels of B12, food-bound B12 absorptions were determined using a body counter in an iron room, and were related to serum total Hcys levels. Food-bound B12 absorption was decreased in 16 patients and in an additional four, absorption of the free vitamin was also decreased. Homocysteine levels were elevated in four of the 16; in three of the four who had both decreased bound and free B12 absorptions, Hcys was elevated. If elevation of the Hcys level indicates tissue deficiency of B12, the 75% incidence of normal levels of Hcys in these patients with low food-bound B12 absorptions suggests the existence of a cohort of patients who may be at risk to develop, but have not yet developed, B12 deficiency. Only long term follow-up will reveal how many ultimately will become B12 deficient.

Adult↗
PubMed1998

Tolerance and determinant hierarchy.

The overall T cell response to a multideterminant antigen consists of the sum of responses to a limited number of different determinants on the protein. Antigen-presenting cells (APCs) are crucial in delimiting the determinants on the protein to which a response will be mounted. This influence is apparent at two levels. First, the determinants that are generated and displayed by APCs in the thymus are pivotal in shaping the T cell repertoire that will be available for responding to antigen determinants in the periphery. Second, antigen processing affects the selection of determinants that become displayed by the various peripheral APC populations that are involved in inducing and promoting a T cell response. We have studied the effect of the display hierarchy on tolerance induction to individual determinants in transgenic mice expressing different serum levels of hen egg lysozyme. We have also analysed aspects of the processing machinery that contribute to shaping the hierarchy of determinant display on MHC class II molecules: proteolysis and reduction of disulfide bonds.

Amino Acids, Diamino↗
PubMed1998

A consensus model for molecular packing of type I collagen.

In this review, recent results from X-ray diffraction studies of tendon are used to develop an understanding of the molecular packing of type I collagen in tendon fibrils. These cover the definition of the unit cell as triclinic, the lateral architecture of molecular packing in a fibril and the molecular packing topology of a structure that gives good agreement with X-ray diffraction data. The proposed model is a 1D staggered left handed microfibril; the molecular orientation of the telopeptides indicates that there are interconnections between microfibrils that may explain the difficulty in isolating individual microfibrillar structures. This is the first structure that defines the absolute molecular packing of molecular segments based on X-ray diffraction data. These results are discussed in the light of direct and indirect evidence relating to molecular packing such as mineralization, natural crosslink position, and biomechanical evidence. The ability of the proposed structure to fulfill many of the structural and biochemical criteria point towards the structure providing a basis for a consensus model of collagen packing.

Animals↗