Search PubMed⌕ Search

Biomedical subjects

M H Becker

Publications and source records attributed to M H Becker.

At least 37 records · Page 2Linked to original sources
PubMed1993

New antiserum against Ki-67 antigen suitable for double immunostaining of paraffin wax sections.

AIMS: To prepare a rabbit antiserum equivalent to MIB 1 to permit the simultaneous assessment of cell proliferation and other markers of interest using double labelling studies. METHODS: Rabbits were immunised with a synthetic peptide deduced from the cDNA sequence coding for the Ki-67 antigen. Serum samples were tested for immunoreactivity using different immunobiochemical methods. RESULTS: A polyclonal antiserum was derived which detects the native as well as recombinant parts of the Ki-67 antigen in different test systems. Furthermore, the antiserum stains the Ki-67 antigen in routinely processed, paraffin wax embedded material. CONCLUSIONS: After antigen unmasking by microwave treatment the antiserum described here represents a powerful tool for the determination of growth fractions even in archival material. It is especially suitable for double staining experiments in combination with monoclonal antibodies.

Amino Acid Sequence↗
PubMed1993

New Ki-67-equivalent murine monoclonal antibodies (MIB 1-3) generated against bacterially expressed parts of the Ki-67 cDNA containing three 62 base pair repetitive elements encoding for the Ki-67 epitope.

BACKGROUND: The monoclonal antibody Ki-67 reacts with a human nuclear cell proliferation-associated antigen that is expressed in all cells that are not in G0. Recently, we could demonstrate that Ki-67 detects a double band in Western blots of proliferating cells with apparent molecular weights of 345 kilodaltons and 395 kilodaltons, respectively. Furthermore, initial molecular biologic data favored the view that the epitope detected by Ki-67 might be encoded by a repetitive 66 bp element. EXPERIMENTAL DESIGN: In order to verify this assumption, parts of the Ki-67 cDNA were bacterially expressed, and the fusion proteins obtained were used to elicit new monoclonal antibodies. The specificities of the new reagents were tested by immunohistochemistry, Western blot, and enzyme-linked immunosorbent assay techniques. RESULTS: The somatic cell fusions revealed a number of antibodies with immunoreactivities comparable to Ki-67. Three antibodies, designated MIB 1-3, were further characterized. Besides the fact that their immunostaining reactivity is identical with that of Ki-67, all new antibodies react in Western blots with native Ki-67 antigen. Furthermore, Western blot and competitive binding assays by enzyme-linked immunosorbent assay clearly demonstrate that MIB 1 and MIB 3, like the original Ki-67 antibody, react with an epitope that is encoded by the 66 bp repetitive element mentioned above. MIB 2, however, reacts with an epitope distinct from this latter structure. In addition, after antigen unmasking by microwave treatment, MIB 1 and MIB 3 detect the Ki-67 antigen in paraffin sections. CONCLUSIONS: Our results demonstrate that it is possible to use bacterially expressed parts of the Ki-67 antigen as immunogen to elicit antibodies that react with the native antigen. While MIB 1 and MIB 3 detect the same or a very similar epitope as the original antibody Ki-67, MIB 2 clearly differs in its fine specificity. Our results provide a circle of evidence that the cDNA sequence thus far determined encodes for the Ki-67 antigen. Furthermore, the new antibodies may become powerful tools for routine histopathology and for further functional characterization of the Ki-67 antigen.

Amino Acid Sequence↗
PubMed1992

Monoclonal antibodies against recombinant parts of the Ki-67 antigen (MIB 1 and MIB 3) detect proliferating cells in microwave-processed formalin-fixed paraffin sections.

The monoclonal antibody Ki-67 reacts with a human nuclear cell proliferation-associated antigen that is expressed in all active parts of the cell cycle. Recently we have raised monoclonal antibodies, MIB 1-3, against recombinant parts of the Ki-67 antigen. These antibodies are true Ki-67 equivalents, as demonstrated by immunostaining of fresh specimens, biochemistry, and molecular biological techniques. Formalin-fixed, paraffin-embedded sections routinely processed for immunohistochemistry failed to stain for Ki-67 and MIB 2. Antibodies MIB 1 and MIB 3 labelled mitotic figures, while non-mitotic proliferating cells were negative under these conditions. However, when dewaxed microwave oven-processed paraffin sections of formalin-fixed tissues were used, MIB 1 and MIB 3 gave strong nuclear staining of those cells presumed to proliferate under a variety of normal and neoplastic conditions. Moreover, routine decalcification or depigmentation techniques did not alter the immunoreactivity of MIB 1 and MIB 3 with microwave-processed paraffin sections. This method is highly reproducible, easy to perform at low cost, and no additional technical skill is needed because after microwave treatment just routine immunohistochemical methods are used. Since we have successfully applied this new method to sections obtained from paraffin blocks stored for a long time (in one case more than 60 years), the assessment of cell kinetics through the detection of Ki-67 antigen is now possible on archival material collected in histopathology departments all over the world.

Antibodies, Monoclonal↗
PubMed1992

Immunobiochemical characterization of the antigen detected by monoclonal antibody IND.64. Evidence that IND.64 reacts with the cell proliferation associated nuclear antigen previously defined by Ki-67.

The immunohistochemical characteristics of the monoclonal antibody IND.64 are very similar to those of the monoclonal antibody Ki-67. The aim of this study was to further characterize this new antibody and to compare it with Ki-67 using immunobiochemical methods. Our results demonstrate that the similarity between the antibodies holds true even at the molecular level. Immunoblot analysis of IM-9-cell lysates with both antibodies showed a double band with apparent molecular weights of 395 kD and 345 kD, respectively. Competition ELISAs using a synthetic peptide derived from the thus far determined Ki-67 cDNA sequence as competitor, indicate that IND.64 may recognize the same epitope as Ki-67. The IND.64 epitope resides at least within a 20 amino acid sequence which also contains the Ki-67 epitope. Since IND.64 is of the IgG2b subclass, while Ki-67 is of the IgG1 subclass, the two antibodies may be useful for double immunostaining. In addition, IND.64 may help in determining the still unknown function of the antigen it recognizes.

Antibodies, Monoclonal↗
PubMed1992

Impact of self-management education on the functional health status of older adults with heart disease.

This paper presents findings from the evaluation of a self-management education program based on self-regulation principles. Older men and women (N = 324) were randomly assigned to program and control groups. Outcomes were measured using the Sickness Impact Profile. Twelve months following baseline data collection, psychosocial functioning of program participants was significantly better than that of controls. Different program effects were noted when results were analyzed by participant gender.

Activities of Daily Living↗
PubMed1992

Monoclonal antibody JC1: new reagent for studying cell proliferation.

AIM: To characterise a newly developed mouse monoclonal antibody JC1 which recognises a nuclear antigen present in proliferating cells in normal tissues and neoplastic lesions, and which is absent in resting cells. METHODS: The methodology was established using a representative range of frozen sections from normal tissues and from certain tumours which were immunostained with antibodies Ki67 and JC1. The molecular weight of the antigen recognised by JC1 was obtained by western blot analysis and this was compared with that of Ki67. IM-9 cell lysates containing Ki67 derived plasmids were also tested with JC1 antibody. RESULTS: Biochemical investigation indicated that the antigen recognised by JC1 gives two molecular weight bands of 212 and 123 kilodaltons, which is distinct from the well characterised anti-proliferation monoclonal antibody Ki67 (395-345 kilodaltons). In addition recombinant Ki67 protein is not recognised by JC1. Immunohistological reactivity was seen in areas known to contain numerous proliferating cells such as lymphoid germinal centres, splenic white matter, cortical thymocytes and undifferentiated spermatogonia. In tumours many cells from adenocarcinomas, oat cell carcinomas, squamous cell carcinomas of lung, and seminomas were labelled by JC1 with a distribution and proportion similar to that seen with Ki67. In normal tissues the only apparent difference was in testis where JC1 stained a considerably greater number of cells than Ki67. In all cases studied the new antibody showed nuclear reactivity only. JC1 did not show any cytoplasmic crossreactivity with squamous cells as is frequently seen with Ki67. CONCLUSION: Antibody JC1, which recognises a nuclear antigen present in proliferating cells, should provide a useful adjunct to Ki67 as a marker of proliferation especially in those cases such as squamous cell carcinomas where a Ki67 index cannot be determined.

Animals↗
PubMed1990

Noncompliance with Universal Precautions Policy: why do physicians and nurses recap needles?

In 1987 the Centers for Disease Control published a Universal Precautions Policy establishing blood and body fluid procedures to be used consistently with all patients. An important and unequivocal Universal Precautions Policy recommendation with regard to avoidance of needlestick injuries is that needles should never be recapped. We examined the recapping-related attitudes and behaviors of physicians and nurses at four large teaching hospitals with patients with acquired immunodeficiency syndrome and with Universal Precautions Policy in-service training programs. Compliance was found to be considerably less than optimal. According to unannounced needle counts in disposal boxes, the percentage of recapped needles was always greater than 25% and exceeded 50% in four instances. Recapping was related to inadequate knowledge, concerns about personal risk, forgetfulness, being "too busy" to follow the Universal Precautions Policy, and the misperception that recapping is a way to avoid needlestick injury. Strategies are suggested to improve and supplement traditional in-service education.

Communicable Disease Control↗
PubMed1989

Recruitment of a large community of pediatricians in a collaborative research project.

To investigate the effects of an educational program on the compliance-enhancing behavior of pediatricians and the subsequent regimen adherence of their patients, it was necessary to enlist the participation of a large number of pediatric practitioners. The physicians had to be motivated to attend two evenings of tutorial training; to enroll their patients in the project; and to complete detailed study documents. Ultimately, 90 of the 97 pediatricians practicing in the community took part. The following factors are felt to have contributed to the widespread participation of the pediatricians: 1) the subject was interesting and of relevance to clinical practice; 2) the study was designed so as not to interfere with office routine; 3) major demands were not made on the patients; 4) due consideration was given to the value of the physicians' participation; and 5) communication between the investigators and the practitioners was facilitated by a liaison pediatrician.

Humans↗
PubMed1989

The Health Belief Model in understanding compliance with preventive recommendations for AIDS: how useful?

The Health Belief Model (HBM) has been applied to a variety of health conditions: most are less threatening and require less complex responses than those arising in the case of AIDS. The utility of the HBM in understanding preventive behaviors in AIDS is examined in a cohort of homosexual men at two different time points. Longitudinal analyses estimated the relationship of indices assessing susceptibility, severity, benefits, and barriers, as well as sociodemographic factors, to sexual behavior across the next 18 months. Analyses further defined these associations in specific subgroups of participants, such as those initially at lower or higher risk. In general, measures of severity and socioeconomic advantage had the most consistently beneficial effect on various measures of behavior. Little or no beneficial effect was observed for other components of the HBM, notably a measure of perceived susceptibility. These analyses suggest that the special features of AIDS may require development of more adequate theoretical frameworks.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Improving pediatricians' compliance-enhancing practices. A randomized trial.

Previous evaluations of continuing medical education (CME) have yielded conflicting results regarding its effects on physician knowledge, performance, and subsequent patient outcomes. Poor adherence by mothers to prescribed pediatric regimens is a separate, but well-documented, problem. In the present study we assessed the ability of CME to: (1) increase the knowledge of pediatricians about compliance-enhancing strategies; (2) increase the performance of these practices by pediatricians; and (3) improve mothers' compliance with antibiotic regimens for their children's otitis media. Ninety pediatricians were randomly assigned to either a control group or one of two CME interventions: tutorial plus printed materials or mailed printed materials only. Following the interventions, data on compliance and on reported behaviors of pediatricians were gathered from a random sample of mothers (N = 771) whose children were being treated for otitis media. Findings indicated that CME increased physician knowledge and compliance-enhancing practices and resulted in improvement in mothers' adherence to therapy.

Child↗
PubMed1988

Social learning theory and the Health Belief Model.

The Health Belief Model, social learning theory (recently relabelled social cognitive theory), self-efficacy, and locus of control have all been applied with varying success to problems of explaining, predicting, and influencing behavior. Yet, there is conceptual confusion among researchers and practitioners about the interrelationships of these theories and variables. This article attempts to show how these explanatory factors may be related, and in so doing, posits a revised explanatory model which incorporates self-efficacy into the Health Belief Model. Specifically, self-efficacy is proposed as a separate independent variable along with the traditional health belief variables of perceived susceptibility, severity, benefits, and barriers. Incentive to behave (health motivation) is also a component of the model. Locus of control is not included explicitly because it is believed to be incorporated within other elements of the model. It is predicted that the new formulation will more fully account for health-related behavior than did earlier formulations, and will suggest more effective behavioral interventions than have hitherto been available to health educators.

Attitude to Health↗
PubMed1988

Perceptions held by obese children and their parents: implications for weight control intervention.

The study was designed to identify some of the psychosocial barriers to compliance in a hospital-based weight control intervention program for adolescents. Forty obese adolescents, 10 to 16 years of age, and their parents were surveyed prior to participation in a behavioral change weight control program at a major teaching hospital. Significant correlations were obtained between weight loss outcome and six factors. In obese adolescents, weight loss was significantly associated with their beliefs regarding: (1) personal control over weight, (2) barriers or difficulty of losing weight, (3) medical problems as a cause of their obesity, (4) family problems as a cause of their obesity, and (5) perceived willingness of family members to diet. It is suggested that greater weight loss in children who perceived more barriers/difficulty and less family willingness to diet may reflect the importance of having realistic expectations related to behavioral compliance. In addition, a positive parental attitude or expectation that the child was less likely to be overweight in the future was associated with greater weight loss compliance. Other parental health beliefs, however, did not generally predict the child's weight loss response to the intervention. The findings lend support to the significance of the adolescent's beliefs regarding weight and family support in explaining weight loss response to a behavioral change intervention program.

Adolescent↗