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Biomedical subjects

M Tucker

Publications and source records attributed to M Tucker.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Culture of blastocysts using sequential media].

The advantages of cultivating human pre-embryos to the stage of blastocites, are well known. The use of media of culture sequential, without the backing of somatic cells, is new. The objective was to cultivate human pre-embryos to the stage of blastocyte to the determine the recuperation indexes, implantation index and pregnancy index in patients subjected to FIVT/TE or ICSI. Once obtained the ovules of patients were injected/inseminated to latter be cultivated for 72 hours using P1 medium at 10% of SSS under mineral oil for, latter, be transferred to a complex medium for blastocites culture for 48 hours, and finally be transferred. Thirteen were included (9 of FIV and 4 of ICSI) obtaining 205 ovules; fertilized 143 and 131 had cellular division. One hundred and twenty one pre-embryos were cultivated to blastocyst stage, from which, 53 reached that stage (43.8%); transferring 28 and freezing 25. In average, 2.1 blastocysts were transferred by patient. There were four pregnancies and one alive newborn, at term for an index of implantation of 14.2% and a pregnancy index of 30.7%. The study shows our initial experience, which demonstrated and acceptable idea of recuperation of blastocysts and pregnancies.

Blastocyst↗
PubMed1999

The Regenstrief Medical Record System: a quarter century experience.

Entrusted with the records for more than 1.5 million patients, the Regenstrief Medical Record System (RMRS) has evolved into a fast and comprehensive data repository used extensively at three hospitals on the Indiana University Medical Center campus and more than 30 Indianapolis clinics. The RMRS routinely captures laboratory results, narrative reports, orders, medications, radiology reports, registration information, nursing assessments, vital signs, EKGs and other clinical data. In this paper, we describe the RMRS data model, file structures and architecture, as well as recent necessary changes to these as we coordinate a collaborative effort among all major Indianapolis hospital systems, improving patient care by capturing city-wide laboratory and encounter data. We believe that our success represents persistent efforts to build interfaces directly to multiple independent instruments and other data collection systems, using medical standards such as HL7, LOINC, and DICOM. Inpatient and outpatient order entry systems, instruments for visit notes and on-line questionnaires that replace hardcopy forms, and intelligent use of coded data entry supplement the RMRS. Physicians happily enter orders, problems, allergies, visit notes, and discharge summaries into our locally developed Gopher order entry system, as we provide them with convenient output forms, choice lists, defaults, templates, reminders, drug interaction information, charge information, and on-line articles and textbooks. To prepare for the future, we have begun wrapping our system in Web browser technology, testing voice dictation and understanding, and employing wireless technology.

Computer Terminals↗
PubMed1999

Positive outcome after preimplantation diagnosis of aneuploidy in human embryos.

usromosomal abnormalities are responsible for a great deal of embryo wastage, which is reflected, at least partially, in decreased implantation and increased miscarriage in older women. To address this problem the transfer of only chromosomally normal embryos previously selected by preimplantation genetic diagnosis (PGD) has been proposed. We designed a multi-centre in-vitro fertilization (IVF) study to compare controls and a test group that underwent embryo biopsy and PGD for aneuploidy. Patients were matched retrospectively, but blindly, for average maternal age, number of previous IVF cycles, duration of stimulation, oestradiol concentrations on day +1, and average mature follicles. All these parameters were similar in test and control groups. Only embryos classified as normal for those chromosomes were transferred after PGD. The results showed that the rates of fetal heart beat (FHB)/embryo transferred between the control and test groups were similar. However, spontaneous abortions, measured as FHB aborted/FHB detected, decreased after PGD (P < 0.05), and ongoing pregnancies and delivered babies increased (P < 0.05) in the PGD group of patients. Two conclusions were obtained: (i) PGD of aneuploidy reduced embryo loss after implantation; (ii) implantation rates were not significantly improved, but the proportion of ongoing and delivered babies was increased.

Aneuploidy↗
PubMed1998

The kin-cohort study for estimating penetrance.

A cross-sectional study may be more feasible than a cohort or case-control study for examining the effect of a genetic mutation on cancer penetrance outside of cancer families. The kin-cohort design uses volunteer probands selected from a population with a relatively high frequency of the mutations of interest. By considering the cancer risk in first-degree relatives of mutation-positive and -negative probands as a weighted average of the risk in carriers and noncarriers, with weights calculated assuming a known mode of inheritance, one can infer the penetrance of the mutations. The estimates of penetrance by age 70 years for three specific mutations in the BRCA1 and BRCA2 genes common among Ashkenazi Jews for the first occurrence of breast or ovary cancer is 63%. The kin-cohort design can be a useful tool for quickly estimating penetrance from volunteers in a setting in which the mutation prevalence is relatively high.

Adult↗
PubMed1998

The role of digital imaging and communications in medicine in an evolving healthcare computing environment: the model is the message.

The decision to use Digital Imaging and Communications in Medicine (DICOM), Health Level 7 (HL7), a common object broker such as the Common Object Request Brokering Architecture (CORBA) or ActiveX (Microsoft Corp, Redmond, WA) or any other protocol for the transfer of DICOM data depends on the requirements of a particular implementation. The selection of protocol is independent of the information model. Our goal as message standards developers is to design a data interchange infrastructure that will faithfully convey the computer-based patient record and make it available to authorized health care providers when and where it is needed for patient care. DICOM accurately and expressively represents the clinically significant properties of images and the semantics of image-related information. The DICOM data model is small and well-defined. The model can be expressed in Standard Generalized Markup Language (SGML) or Object Management Group Interface Definition Language or other common syntax-and can be implemented using any reliable communications protocol. Therefore our opinion is that the DICOM semantic data model should serve as the basis for a logically equivalent set of specifications in HL7, CORBA, ActiveX, and SGML for the interchange of biomedical images and image-related information.

Computer Communication Networks↗
PubMed1998

RESEARCH: Perceptions of Risk Associated with Use of Farm Chemicals: Implications for Conservation Initiatives

/ Data were collected from 245 farmers within the Darby Creek hydrologic unit in central Ohio to assess perceptions of risk associated with use of farm chemicals. Farmers were asked to evaluate the level of risk associated with use of agricultural chemicals for water quality, food safety, food quality, health of applicator, health of farm animals, wildlife, beneficial plants, beneficial insects, and human health. Study findings revealed that respondents perceived use of farm chemicals posed little or no threat to any of the assessed items. A composite index was formulated from the responses to the nine items and was titled Perceived Risk. Variance in the Perceived Risk index was regressed against social learning variables. The findings revealed that approximately 32% of the variance was explained by the predictive variables included in the model. It was concluded that the theoretical perspective was somewhat useful for understanding perceptions held about agricultural chemical use at the farm level. The findings are discussed in the context of future conservation and educational-information programs within the study region.KEY WORDS: Risk perception; Risk assessment; Groundwater; Pesticide contamination; Food safety; Environmental quality

Journal Article↗
PubMed1998

On the relations between seen objects and components of potential actions.

Accounts of visually directed actions usually assume that their planning begins with an intention to act. This article describes three experiments that challenged this view through the use of a stimulus-response compatibility paradigm with photographs of common graspable objects as stimuli. Participants had to decide as fast as possible whether each object was upright or inverted. Experiments 1 and 2 examined the effect of the irrelevant dimension of left-right object orientation on bimanual and unimanual keypress responses. Experiment 3 examined wrist rotation responses to objects requiring either clockwise or anticlockwise wrist rotations when grasped. The results (a) are consistent with the view that seen objects automatically potentiate components of the actions they afford, (b) show that compatibility effects of an irrelevant stimulus dimension can be obtained across a wide variety of naturally occurring stimuli, and (c) support the view that intentions to act operate on already existing motor representations of the possible actions in a visual scene.

Attention↗
PubMed1998

Use of noncontingent reinforcement in the treatment of challenging behavior. A review and clinical guide.

Recently, noncontingent reinforcement (NCR) has been used to reduce challenging behavior in persons with developmental disabilities. In this context, NCR involves reinforcement on a fixed-time schedule irrespective of behavior. The present article reviews studies involving NCR for the treatment of challenging behavior. Based on this review, a clinical guide for the implementation of NCR is delineated. NCR appears to depend on ensuring that reinforcement matches the function of the challenging behavior. Initially, noncontingent reinforcement should be provided on a continuous basis. The schedule can then be faded from continuous reinforcement to a more appropriate level in a number of ways. NCR can also be combined with additional educationally oriented interventions to promote skill development. Given its ease of implementation and other potential advantages, NCR would appear particularly relevant for applied settings. The clinical guide may offer some assistance to practitioners.

Adult↗
PubMed1997

Recombinant human osteogenic protein 1 in the rat mandibular augmentation model: differences in morphology of the newly formed bone are dependent on the type of carrier.

Recombinant human osteogenic protein 1 (rhOP1), also known as bone morphogenetic protein 7, was investigated in a newly developed experimental model, the rat lateral mandibular augmentation model. Algipore and Bio-Oss Block were applied as carrier materials. Extensive induction of newly formed bone was demonstrated on the test side containing rhOP1 and did not occur on the control side without rhOP1. The interstitial bone formation was limited to the augmented area and was not observed in the surrounding masseter muscle. The morphology of the newly formed bone differed in both carrier systems, which may be an important characteristic for the clinical indication of carrier systems in combination with bone morphogenetic proteins.

Animals↗
PubMed1997

Recombinant human osteogenic protein-1 induces dentin formation: an experimental study in miniature swine.

It was the aim of the present study to investigate the induction of dentin formation by recombinant human osteogenic protein-1 (hOP-1). In 4 adult miniature pigs a total of 16 teeth with artificially exposed dental pulps were capped with 3 mg of a complex of recombinant hOP-1 in collagen matrix (2.5 micrograms/mg), collagen matrix alone, or calcium hydroxide paste. Teeth were removed in block section after a healing period of 5 weeks. Decalcified sections were processed for light microscopy and histomorphometric analysis. In hOP-1 treated teeth substantial amounts of hard tissue formation (osteodentin and tubular dentin) had consistently led to a complete bridging of the defects. Less dentin formation was seen after calcium hydroxide application. In control defects collagen matrix alone failed to form complete dentin bridges. Recombinant human osteogenic protein-1 in a collagen carrier matrix appeared to be suitable as a bio-active capping agent for surgically exposed dental pulps.

Animals↗
PubMed1997

Treatment-related chromosome abnormalities in human embryos.

Mosaicism was studied in good quality embryos from four different centres in order to assess the effects of follicular induction and exposure to laboratory conditions on chromosomal status. The donated embryos were fully biopsied and analysed by fluorescence in-situ hybridization using probes for chromosomes X, Y, 13, 18 and 21, simultaneously. The number of abnormal cells present indicated the division at which mosaicism first occurred (4/4 cells at first division, 2/4 cells at second, 2/8 at third). The rate of mosaicism in embryos from different centres varied greatly (P < 0.001). Most of the mosaic embryos were obtained before 1991. In one clinic increased mosaicism was found in embryos obtained before 1991 when compared to embryos obtained thereafter. The results suggest that certain culture conditions and/or hormonal stimulation protocols may induce chromosomal abnormalities and partly explain differences in pregnancy rates between in-vitro fertilization centres.

Biopsy↗
PubMed1997

A practical strategy to increase participation and reduce challenging behavior during leisure skills programming.

The effects of prompting, reinforcer sampling, and assistance on participation and challenging behavior of two adults with severe disabilities were examined under three conditions during a leisure program. For baseline, leisure materials were absent, but there was opportunity for social interaction. Next, leisure materials were provided, but participants were neither prompted nor assisted to use these materials. During intervention, participants sampled the materials and were assisted to use each item during a 5-minute prompting sequence. A reversal design demonstrated that the prompting sequence was associated with increased participation and reduced challenging behavior. These improvements were maintained as the frequency of the prompting sequence was reduced from four times to once per session.

Adult↗
PubMed1996

Pregnancy-related mortality in the United States, 1987-1990.

OBJECTIVE: To use data from the Centers for Disease Control and Prevention's (CDC) Pregnancy-Related Mortality Surveillance System to examine trends in pregnancy-related mortality and risk factors for pregnancy-related death. METHODS: In collaboration with ACOG and state health departments, the Pregnancy-Related Mortality Surveillance System has collected information on all deaths caused by pregnancy since 1979. Multiple data sources were used, including national death files, state health departments, maternal mortality review committees, individuals, and the media. As part of the initiation of the Pregnancy-Related Mortality Surveillance System in 1987, CDC staff contacted state health department personnel and encouraged them to identify and report pregnancy-related deaths. Data were reviewed and coded by experienced clinicians. Pregnancy-related mortality ratios (pregnancy-related deaths per 100,000 live births) were calculated. RESULTS: After decreasing annually after 1979, the reported pregnancy-related mortality ratio increased from 7.2 in 1987 to 10.0 in 1990. This increase occurred among women of all races. A higher risk of pregnancy-related death was found with increasing maternal age, increasing live-birth order, no prenatal care, and among unmarried women. The leading causes of pregnancy-related death were hemorrhage, embolism, and hypertensive disorders of pregnancy. During the periods 1979-1986 and 1987-1990, the cause-specific pregnancy-related mortality ratios decreased for deaths due to hemorrhage and anesthesia, whereas pregnancy-related mortality ratios due to cardiomyopathy and infection increased. The leading causes of death varied according to the outcome of the pregnancy. CONCLUSION: Increased efforts to identify pregnancy-related deaths have contributed to an increase in the reported pregnancy-related mortality ratio. More than half of such deaths, however, are probably still unreported. Adequate surveillance of pregnancy-related mortality and morbidity is necessary for interpreting trends, identifying high-risk groups, and developing effective interventions.

Adolescent↗
PubMed1996

Cloning of the alpha and beta ovine thyroid hormone receptor cDNAs.

Thyroid hormones modulate critical responses in a variety of tissues during development. While the mechanisms underlying many of these responses are uncertain, specific thyroid hormone nuclear receptor proteins likely play key roles in these processes. Many studies investigating the perinatal role of thyroid hormones in maturation have focused on events occurring in the developing rodent. However, the ovine fetus also serves as a useful model for human fetal thyroid system function. To extend the utility of the ovine model, the cDNAs representing the ovine family of nuclear thyroid receptors have been cloned, sequenced, and used to characterize mRNA species in ovine brain.

Amino Acid Sequence↗
PubMed1996

Preliminary experience with human oocyte cryopreservation using 1,2-propanediol and sucrose.

Feasibility of cryopreservation of mature human oocytes using 1, 2-propanediol and sucrose was studied initially utilizing 1 and 2 day old unfertilized oocytes. Of these 285 aged oocytes 55% survived thawing, and 41% of 128 oocytes inseminated by single sperm intracytoplasmic injection (ICSI) fertilized normally. Limited embryonic development occurred in 51% of these embryos (n = 27) observed for the next 4 days. Cryosurvival of fresh donated oocytes (n = 81) was poorer (n = 20; 24.7%), while fertilization (n = 13; 65%) and embryo development (100%) was good prior to uterine transfer on day 3. Eight oocyte recipient cycles were undertaken, in which cryopreserved donated oocytes were thawed and inseminated by ICSI. Five of these cycles reached embryo transfer, and three pregnancies were initiated though none went successfully to term. Oocyte cryopreservation will ultimately facilitate oocyte donation procedures; however, cryosurvival of fresh frozen oocytes must be improved to at least the degree observed with aged unfertilized oocytes.

Cell Survival↗
PubMed1995

Reaction of neprilysin (neutral endopeptidase) and thermolysin with cyclic peptides.

The reaction of neprilysin and thermolysin with a series of cyclic beta-turn peptides, varying in length from 6 to 14 residues, has been studied. All of the cyclic peptides bind to neprilysin with their affinity increasing from 113 microM for the 6-membered ring to 17 microM for the 14-membered ring. The 6-membered cyclic peptide was not hydrolyzed. However, kcat increased from 1.5 min-1 for the 8-membered cyclic peptide to 148 min-1 for the 14-membered cyclic peptide. With thermolysin binding of the 6- or 8-membered cyclic peptides was not detected. The Km values for the 10-, 12-, and 14-membered cyclic peptides were all in the 100 microM range. With thermolysin, kcat increased from 7 min-1 for the 10-membered cyclic peptide to 27,000 min-1 for the 14-membered cyclic peptide. Cyclic peptides were all cleaved at N-terminally directed sites. Modeling of the binding of a cyclic peptide, structurally similar to the 12-membered cyclic beta-turn peptide described above, into the active site of thermolysin shows that only half of the substrate makes contact with the enzyme and that only residues on one side of the peptide could fit into the active site. From these studies it is concluded that key factors which influence catalysis include not only peptide sequence, but the flexibility of the peptide and the orientation of the S'1 residue in a cyclic peptide.

Amino Acid Sequence↗