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Biomedical subjects

L Dawson

Publications and source records attributed to L Dawson.

At least 19 recordsLinked to original sources
PubMed1998

Mutations of the human immunodeficiency virus type 1 p6Gag domain result in reduced retention of Pol proteins during virus assembly.

One of the crucial steps in the assembly of the human immunodeficiency virus type 1 (HIV-1) and other retroviruses is the incorporation and retention of all the key viral enzymes in released virions. The viral enzymes protease, reverse transcriptase, and integrase of HIV-1 are initially synthesized as Gag-Pol fusion polyproteins. It has been shown that the incorporation of Gag-Pol polyproteins during virus assembly requires the Gag domains that are shared by the Gag and Gag-Pol precursors. We now report that truncation of the C-terminal p6 domain of HIV-1 Gag, which is present in the Gag precursor but not in the Gag-Pol precursor, drastically reduced the amount of Pol proteins in the mutant virions. Mutations in the lentivirus conserved motif P(T/S)APP in p6 also drastically reduced the amount of Pol proteins in mutant virions. The steady-state levels of Gag-Pol precursors and cleaved Pol proteins in the transfected cells were not affected by mutations in p6. The incorporation of unprocessed Gag-Pol precursors into p6 mutant virions was detected when the viral protease was mutated, suggesting that the interactions among mutant Gag molecules and Gag-Pol precursors were not significantly affected. These results suggest that the p6 domain of HIV-1 Gag may play an important role in recruiting or retaining cleaved Pol proteins during virus assembly.

Amino Acid Sequence↗
PubMed1997

The role of reduced ear size in the prenatal detection of chromosomal abnormalities.

A prospective ultrasound study was performed between 18 and 38 weeks' gestation on 29 fetuses in a high-risk population, defined by the presence of structural anomalies, in order to investigate the usefulness of fetal ear measurements in the prenatal prediction of chromosomal abnormality. The prevalence of abnormal chromosomes was 34 per cent. The sensitivity (SE), specificity (SC), positive predictive values (PPV), and negative predictive values (NPV) of ear length for the detection of chromosomal abnormality were 80, 84.2, 72.7 and 88.9 per cent. The SE, SC, PPV, and NPV of ear width were 40, 94.7, 80 and 75 per cent. Fetal ear measurements may be a useful adjunct to the various ultrasound parameters in the prenatal detection of chromosome abnormality in a high-risk population of fetuses with structural anomaly(ies).

Adolescent↗
PubMed1996

Detection of Cryptosporidium parvum oocysts in faeces: comparison of conventional coproscopical methods and the polymerase chain reaction.

Conventional and coproscopical methods were compared with the polymerase chain reaction (PCR) for the detection of Cryptosporidium oocysts in bovine faeces. Oocysts were not detected in samples seeded with 10,000 oocysts following formol ether sedimentation and examination using auramine phenol (AP) or by immunofluorescent (IF) staining. When oocysts were concentrated using sucrose flotation the threshold of detection was 4000 oocysts per gram for both staining methods. Following salt flotation 4000 oocysts per gram could be reliably detected by AP staining but the detection limit was increased to 6000 oocysts per gram using IF staining. The recovery of oocysts was significantly less than expected for all techniques. A specific PCR coupled with immunomagnetic particle separation (IMS) of samples detected five oocysts per ml of diluted faeces, which corresponds to 80-90 oocysts per gram. Even allowing for the dilution of formed faecal samples, required for IMS, this represents an increase in sensitivity of several orders of magnitude over the conventional corpodiagnostic methods.

Animals↗
PubMed1995

Squamous cell carcinoma of perineal urethrostomy.

Urethral malignancies are rare while only few cases of urethral carcinoma following urethroplasty have been reported in the literature. We present a case of squamous cell carcinoma at perineal urethrostomy.

Carcinoma, Squamous Cell↗
PubMed1995

Influence of prepartum protein and energy concentrations for dairy goats during pregnancy and early lactation.

Sixty-three multiparous Alpine does were blocked by pregnancy type (single vs. multiple) on d 90 of pregnancy and assigned to one of nine diets to evaluate the interaction of prepartum protein and energy intake on BW change, kidding, and subsequent production and composition of milk. Treatments were factorial with three percentages of CP (8.5, 11.5, and 14.5% of DM) and three concentrations of metabolizable energy (1.80, 2.16, and 2.53 Mcal/kg of DM). Does were fed for ad libitum intake during pregnancy and switched to a lactation diet (16% CP and 2.35 Mcal of metabolizable energy/kg of DM) after parturition. Milk production and composition were recorded for the first 15 wk of lactation. Prepartum BW gain increased quadratically as protein amount increased but was unaffected by energy. Kidding rate, litter weight, and gestation length were unaffected by protein or energy amounts. Milk production in the subsequent lactation increased quadratically in response to prepartum CP (2.59, 3.26, and 3.07 kg/d for 8.5, 11.5, and 14.5% CP, respectively). Milk production increased linearly in response to prepartum metabolizable energy concentration (2.63, 3.05, and 3.26 kg/d for 1.80, 2.16, and 2.53 Mcal/kg of DM, respectively). Milk fat percentage increased linearly in response to increased prepartum energy. Production of milk fat, protein, SNF, FCM, and SCM were affected quadratically by increased prepartum CP and linearly by prepartum energy, following the pattern for milk production. The present recommendations for prepartum CP and energy appear to be adequate for gestation and subsequent lactation performance of dairy goats.

Animals↗
PubMed1992

Human lymphokine-activated killer cells are cytotoxic against cells infected with Toxoplasma gondii.

Experiments were conducted to determine whether human lymphokine-activated killer (LAK) cells are cytotoxic against cells infected with Toxoplasma gondii. Nylon wool nonadherent (NWNA) peripheral blood lymphocytes, as well as purified natural killer cell (NK) (CD3- CD16+ CD56+) and T (CD3+ CD16- CD56-) cells obtained from five healthy T. gondii seronegative volunteers exhibited minimal cytotoxic activity against T. gondii-infected cells. When standard LAK (S-LAK) cell preparations were induced by incubation of NWNA cells with recombinant interleukin 2, induction of remarkable cytotoxic activity against T. gondii-infected cells. When standard in LAK cell preparations from each of the volunteers. The phenotype of the LAK precursor and effector cells varied depending on the target cell used. Whereas the precursor and the effector cells of most of the LAK activity against K562 and Daudi cells were cells with NK phenotype, when T. gondii-infected cells were used as targets, both cells with NK and T cell phenotypes were precursors and effectors of the lysis. When cytotoxic activity of S-LAK cells was compared with the activity of adherent LAK (A-LAK) cells, A-LAK cells displayed higher cytotoxic activity against T. gondii-infected cells, as well as against K562 and Daudi cells. Cold target inhibition experiments suggested that there is a subset of LAK effector cells capable of lysing both T. gondii-infected cells and Daudi cells, whereas other subsets preferentially or exclusively lyse one of these target cells.

Animals↗
PubMed1991

Surgical correction of the Wolff-Parkinson-White syndrome.

The results of corrective surgery in 75 consecutive patients with Wolff-Parkinson-White (WPW) syndrome are reported. There were 47 male and 28 female patients with a median age of 27 years. Intraoperative mapping disclosed 88 accessory pathways, of which 83 were successfully divided at the primary operation without mortality. Two patients underwent successful reoperation at three days and two years respectively. Patient success rates were 93% and 96% for first and total operations. Complications, usually minor, occurred in 20 patients, including permanent pacemaker implantation in two. Surgical correction of WPW syndrome is recommended as a safe alternative to lifelong medical treatment.

Adolescent↗
PubMed1986

Cocklebur poisoning in cattle.

Cocklebur poisoning occurred in a herd of cattle in Oklahoma during the month of July. The poisonous dicotyledonary stage of cocklebur plant growth usually occurs during the early spring in Oklahoma. In this instance, dicotyledonary sprouts were in a lowland pasture adjacent to a river. Sprouting and growth occurred after receding water and hot dry weather had created favorable conditions for germination. The diagnosis was made on the basis of the finding of the dicotyledonary stage of plant growth and evidence of the plants having been grazed, as well as the clinical signs, gross necropsy findings, and histopathologic findings in the affected cattle.

Animals↗
PubMed1982

The role of health education in public policy development.

Health educators should view policy development as a unit of professional practice analogous to the individual, the small group, the community, and the organization. The impact of policy on other units of practice and on people served by health educators is too great and the competition for scarce resources for health and human services is too keen to be disregarded. An increasingly active role in the policy process is, therefore, vital to the profession. Unfortunately, many health educators find an active role strange and lack guidelines for effective policy intervention. This paper attempts to mediate that situation. First a conceptual framework is offered. Operational definitions of important terms are given, including policy, public policy, social policy, health policy, and health education policy. A model of the policy development process is presented, detailing the purpose and dynamics of several steps: establishing problem awareness, setting goals and objectives, selecting a course of action, designing alternative courses of action, analyzing policy, assigning implementation responsibility, implementing, and evaluating. Then five categories of intervention strategies encompassing 16 individual suggested roles ranging from indirect influence to direct political involvement are presented. The categories are: acting as a source of policy information, providing technical assistance, organizing, influencing policymakers, and taking direct political action.

Consultants↗
PubMed1981

Consumer participation and influence in a Health Systems Agency.

Consumer participation and influence were studied in one Health Systems Agency in the southeastern United States over a 20-month period (July 1976--February 1978). Consumer board members were found to be significantly less influential in agency decision making than were provider board members. This difference in influence existed even though virtually no difference existed between consumers' and providers' levels of participation. Consumer board members, while representing minority and nonminority, and both rural and nonrural groups, tended nevertheless also to be middle-class, middle-income individuals. Low-income and working-class groups were underrepresented on the board of the Health Systems Agency. Furthermore, consumer representatives tended to be satisfied with and have access to health care.

Adolescent↗
PubMed1981

Persistent phantom limb pain.

The role of psychological factors in 10 patients with painful phantom limbs was investigated by means of a questionnaire and interviews. The hypotheses were that the severity of pain would be positively correlated with their present personal problems and attitudes and with experience of pain in the limb before amputation. The first hypothesis was confirmed but the second was not.

Adaptation, Psychological↗
PubMed1980

Analysis of health education sections of health systems plans.

Health Systems Agencies are required by federal guidelines to plan for and provide educational opportunities for residents of their health service areas. A study was conducted of 9 health education components of health systems plans developed by HSAs in Region III. The health education plans were analyzed and scored using the "Health Education Plan Scorecard" developed by Sullivan and adapted by the present authors. Specifically this modified scorecard consists of eight dimensions of the health education planning process: Involvement, Principles and Practice of Health Education, Defining Problems, Setting Goals and Objectives, Recommending Actions, Obtaining Resources, Planning for Implementation, and Planning for Evaluation. Ratings were generally higher on the first five dimensions of the scorecard. The last three dimensions produced lower scores. The overall average score was 41 points out of a possible 100. Thus indicating the general overall low scores received by the plans. The paper includes 18 recommendations to HSAs for improving the quality of health education plans. A key recommendation is that the Health Education Plan Scorecard should be used as a guide and check list during the plan development process.

Evaluation Studies as Topic↗
PubMed1978

Midwifery, 1977.

On January 1, 1974, an autonomous midwifery service was formed at Roosevelt Hospital in New York City to provide an obstetric service to "private" patients. While the autonomy was complete, physician consultation and participation provided by the "full-time or senior resident" staff were always available. We are now aware that this plan as opposed to any other, provided the ingredient of consumer-desired empathy of the midwife coupled with instant obstetric expertise that assured every patient the availability of modern obstetric practice. Four hundred and fifty-four patients cared for by midwives were compared to a random sample of 500 patients cared for by attending obstetricians. A striking similarity in the two groups was evident. Certain items, such as operative deliveries, were higher in the private patient group. The midwifery group had a low incidence of complications, but the incidence of acute complications made it apparent that an operating room suite must be immediately available. It is eminently clear that a low-risk group can be identified but there is no possible way to identify a "no risk" population.

Adolescent↗
PubMed1978

Determinants of consumer influence in a health systems agency.

An 18-month study of consumer participation and influence in a Health Systems Agency (HSA) found consumer board members to be less influential than provider board members in agency decision-making. In an effort to investigate causes of the influence deficit experienced by consumer HSA board members three issues were studied: staff attitudes toward consumer participation; board member degree of representative accountability; and board member attitudes concerning commitment to consumer participation, commitment to health planning, health services attitude, and feelings of social powerlessness. Results indicated that staff members were favorable toward the concept of consumer participation. They recognized a lack of low-income minority participation, but they did not provide support or allocate resources to enhance consumers' ability to participate. Providers were less committed to consumer participation, felt more socially powerful, and had greater representative accountability than did consumers. Several strategies for increasing consumer influence in HSA decision-making processes are proposed.

Attitude of Health Personnel↗