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Biomedical subjects

M D Andersen

Publications and source records attributed to M D Andersen.

12 recordsLinked to original sources
PubMed2000

Cytochromes P-450 from cassava (Manihot esculenta Crantz) catalyzing the first steps in the biosynthesis of the cyanogenic glucosides linamarin and lotaustralin. Cloning, functional expression in Pichia pastoris, and substrate specificity of the isolated recombinant enzymes.

The first committed steps in the biosynthesis of the two cyanogenic glucosides linamarin and lotaustralin in cassava are the conversion of L-valine and L-isoleucine, respectively, to the corresponding oximes. Two full-length cDNA clones that encode cytochromes P-450 catalyzing these reactions have been isolated. The two cassava cytochromes P-450 are 85% identical, share 54% sequence identity to CYP79A1 from sorghum, and have been assigned CYP79D1 and CYP79D2. Functional expression has been achieved using the methylotrophic yeast, Pichia pastoris. The amount of CYP79D1 isolated from 1 liter of P. pastoris culture exceeds the amounts that putatively could be isolated from 22,000 grown-up cassava plants. Each cytochrome P-450 metabolizes L-valine as well as L-isoleucine consistent with the co-occurrence of linamarin and lotaustralin in cassava. CYP79D1 was isolated from P. pastoris. Reconstitution in lipid micelles showed that CYP79D1 has a higher k(c) value with L-valine as substrate than with L-isoleucine, which is consistent with linamarin being the major cyanogenic glucoside in cassava. Both CYP79D1 and CYP79D2 are present in the genome of cassava cultivar MCol22 in agreement with cassava being allotetraploid. CYP79D1 and CYP79D2 are actively transcribed, and production of acyanogenic cassava plants would therefore require down-regulation of both genes.

Amino Acid Sequence↗
PubMed1997

Heterologous expression and characterization of wild-type and mutant forms of a 26 kDa endochitinase from barley (Hordeum vulgare L.).

To investigate structure-function relationships in plant chitinases, we have developed a heterologous expression system for the 26 kDa endochitinase from Hordeum vulgare L. (barley). Escherichia coli cells harbouring the gene in a T7 RNA polymerase-based expression vector synthesized completely insoluble recombinant protein under standard induction conditions at 37 degrees C. However, a concentration of soluble recombinant protein of approx. 15 mg/l was achieved by inducing bacteria at low temperature (15 degrees C). Recombinant endochitinase was purified to homogeneity and shown to be structurally and functionally identical to the seed protein. An average of three disulphide bonds are present in the recombinant enzyme, consistent with the number found in the natural form. The seed and recombinant proteins showed the same specific activity towards a high-molecular-mass substrate and exhibited similar anti-fungal activity towards Tricoderma reesei. Site-directed mutagenesis was used to replace residues that are likely to be involved in the catalytic event, based on structural similarities with lysozyme and on sequence alignments with related chitinases. The Glu67-->Gln mutation resulted in a protein with undetectable activity, while the Glu89-->Gln mutation yielded an enzyme with 0. 25% of wild-type specific activity. This suggests that two acidic residues are essential for catalytic activity, similar to the situation with many other glycosyl hydrolases. Examination of conserved residues stretching into the proposed substrate binding cleft suggests that Asn124 also plays an important functional role.

Chitinases↗
PubMed1996

Purification of the bovine xanthine oxidoreductase from milk fat globule membranes and cloning of complementary deoxyribonucleic acid.

The amino acid sequence of the bovine xanthine oxidoreductase was determined by cloning and sequencing cDNA clones encoding the enzyme. Partial amino acid sequence corresponding to 54% of the total sequence were also determined from purified bovine milk xanthine oxidoreductase, showing identity with the translated cDNA sequence. The cDNA of 4719 nucleotides included a 5' untranslated region of 96 nucleotides, an open reading frame encoding a xanthine oxidoreductase of 1332 amino acid residues, and a 3' untranslated region of 624 nucleotides including two polyadenylation signals and a poly (A) tail of 74 nucleotides. The identity between the amino acid sequence of the bovine xanthine oxidoreductase and xanthine oxidoreductase from mammalian species was 86 to 90%.

Amino Acid Sequence↗
PubMed1993

LIGHT model: an effective intervention model to change high-risk AIDS behaviors among hard-to-reach urban drug users.

Two thousand thirty-three hospital emergency room (ER) patients who were current, active injecting drug users (IDUs) were voluntary participants in a pretest, posttest research project which utilized a nursing model, the Personalized Nursing LIGHT Model, as a counseling approach to decrease high-risk AIDS behaviors. The LIGHT Model works by directly improving well-being and thereby indirectly decreasing high-risk behaviors associated with AIDS. Addicts from an urban ER in each of three cities (Detroit, Michigan; Brooklyn, New York; and Baltimore, Maryland) were treated with teams consisting of nurses and indigenous outreach workers. Posttest data were gathered on 995 of the clients who received the Personalized Nursing LIGHT Model teaching and counseling intervention. In a posttest at least 3 months after the initial interview, these IDUs reported a significant increase in well-being, t(530) = -11.77; p < .001, and significant reductions in frequency of IV heroin use, z = -18.4; p < .001, IV cocaine use, z = -16.0; p < .001, and IV speedball use, z = -14.3; p < .001, as well as significant decreases in sharing of cookers (a type of drug-using equipment), z = -13.8; p < .001, and other high-risk behaviors associated with AIDS acquisition and transmission. At a second posttest, at least 6 months after the initial interview, these results were unchanged.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The consciousness rainbow: an explication of Rogerian field pattern manifestations.

The consciousness rainbow is a heuristic designed to be used in nursing practice in conjunction with the personalized nursing practice model based on Rogers' science of unitary human beings (Rogers, 1970, 1990). The first phase in practicing nursing is pattern manifestation appraisal, followed by deliberative mutual patterning. This article presents pattern manifestation appraisal by describing patterns associated with "being," "well-being," and "not being." Clients who enter well-being via another dimension are encouraged to experience "being" in the present as a step toward genuine well-being.

Consciousness↗
PubMed1989

Personalized nursing LIGHT model. Love, Intend, Give, Help, Touching.

The Personalized Nursing LIGHT model is a prescriptive model for nursing. It is a model for nursing practice derived from a synthesis of Aristotle's theory of ethics and Martha E. Rogers' science of unitary human beings. The LIGHT model provides a mechanism for nurses to assist clients to improve their sense of well-being. The authors believe that improving well-being is the focus of nursing. Using principles synthesized from Aristotle and Rogers, clients are encouraged to use their talents in the pursuit of well-being and happiness in an increasingly complex world.

Ethics, Nursing↗
PubMed1989

Substance abuse in women: relationship between chemical dependency of women and past reports of physical and/or sexual abuse.

The purpose of this research was to describe a group of chemically dependent females who were involved with the criminal justice system and note if they reported histories of physical/sexual abuse. Data for this study were obtained from Andersen's 1986 research project funded by the Michigan Department of Corrections and Wayne State University. The findings showed that 19.7% reported histories of sexual abuse and that 27% reported histories of physical/sexual abuse prior to incarceration. These findings suggest a need for a sexual assessment tool and for further research on the relationships of sexual/physical abuse and chemical dependency.

Adolescent↗
PubMed1986

Personalized nursing: an effective intervention model for use with drug-dependent women in an emergency room.

One hundred and fifty five drug-dependent women in an urban hospital emergency room in Detroit, Michigan, were the subjects for this 3-year exploratory field study. Subjects were women who told the emergency room staff that while they wanted assistance with their presenting health problems, they wanted no assistance with their drug addiction. The women were randomly assigned to either the experimental or control study group. Both groups received a pretest in the emergency room, a posttest between 8 and 12 weeks after their emergency room visit, and a follow-up test 6 months after the posttest. In addition, the experimental women were seen by project nurses, primarily in their homes, for a maximum of eight visits on a once-a-week basis. The experimental women were treated using "Personalized Nursing," a nursing intervention model, which focused on providing assistance for client-identified concerns. It was hypothesized that interaction with the Personalized Nursing Intervention Model would be associated with: a decrease in daily drug cost and a decrease in perceived stress. Results show that while there were no differences between the study groups at the pretest interview, the experimental group reported a lower daily drug cost (F(1, 95) = 2.90; p = 0.09), a lower daily heroin cost (U = 165; p = .01), less perceived stress (F(1, 84) = 3.00; p = .09) and emotional distress (F(1, 83) = 3.70; p = .06) than control subjects at the 8-week posttest. The experimental subjects also reported less perceived stress (t(65) = -2.35; p = .02) at 6-month follow-up than control subjects. It was found that results could be improved if members of the experimental clients' social networks were treated simultaneously and if project nurses were correctly utilizing the model. Implications for substance abuse treatment programs are discussed. The encouraging results of this exploratory study warrant follow-up and replication.

Adaptation, Psychological↗
PubMed1985

Personalized nursing: an effective intervention model for use with drug-dependent women in an emergency room.

The study indicates that nurses can affect stress and drug use in addicted women. At the 8-week posttest, daily drug cost and daily heroin costs had gone down for the experimental group. However, at the 6-month posttest, daily drug cost and daily heroin cost for the experimental group increased, although it did not reach its initial pre-intervention levels. The increase in drug costs at 6-month followup is probably a result of the lack of nursing intervention after the 8-week period. Interestingly, both the drug costs and heroin costs of the control group went down at 6 months. In other words, the control group decreased use also, only at a slower pace. What accounted for this decrease in use by the control group at 6 months? Several speculations are offered. The single Personalized Nursing Intervention counseling in the ER may have had an impact on the client. Controls who had had the single intervention in the ER were receptive to followup and were easily found. (Originally the single intervention in the ER was not part of the design. However, about 20 clients who had not had Personalized Nursing Intervention in the ER but who just answered the initial questionnaire were never found for followup. Because of the followup and ethical considerations, project staff members instituted the single ER intervention.) Another speculation is that of "burnout," a phenomenon that can be seen in both experimental and control groups. The mean age of the total population was 28.5, number of times arrested was 7.25, and age at first drug use was 16. It appeared that the following factors evoked a desire for change in these women: 1) leading a drug lifestyle for so many years, 2) the approach of age 30, 3) entrance into adolescence of their own children, and 4) the ER episode. Personalized Nursing Intervention could be considered a catalyst toward lifestyle change. Examination of daily drug cost and the Ireton emotional distress score showed trends indicating that the experimentals with network participation made larger gains than the control group or experimentals without networks. Further study on the use of client networks in treatment is indicated.

Adult↗
PubMedDate not supplied

Nurses decrease barriers to health care by "hyperlinking" multiple-diagnosed women living with HIV/AIDS into care.

The Well-Being Institute (WBI), a community-based nursing organization in Detroit, Michigan, has developed and put into practice innovative intervention and service delivery models to assist HIV-positive women who have a history of substance abuse and mental illness. These multiple-diagnosed women are known to have special problems and barriers to accessing health care. The service delivery model is based on "hyperlinking" women into hard-to-get health care appointment slots through nurses' personal contacts in health care clinics. The intervention model is the personalized nursing LIGHT model. This article describes the service delivery and intervention models and discusses outcomes of the WBI Women's Intervention Program in practice. The program locates HIV-positive, substance-abusing women; enrolls them in primary medical and mental health care; and helps retain them in health care. The results of the model in practice demonstrate its success in hyperlinking hard-to-reach and hard-to-serve HIV-positive women with health care and other needed services and resources. In addition, these multiple-diagnosed women have shown positive effects with respect to improved sense of well-being and decreased psychosocial distress.

Adult↗