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Biomedical subjects

J Michael

Publications and source records attributed to J Michael.

At least 19 recordsLinked to original sources
PubMed2007

Surface modification of titanium-based alloys with bioactive molecules using electrochemically fixed nucleic acids.

A new method of surface modification for titanium (alloys) with bioactive molecules was developed with the intention of providing a new basis of implant adaptation for particular requirements of certain medical indications. Nucleic acid single strands are fixed electrochemically via their termini (regiospecifically) by growing an oxide layer on Ti6Al7Nb anodically. It could be shown that they are accessible to subsequent hybridization with complementary strands at physiological pH. Amount of nucleic acids immobilized and hybridized were determined radioanalytically using 32P-labelled nucleic acids. Stable fixation was attained at and above potentials of 4 V(SCE). Up to 4 pmol/cm2 of nucleic acid single strands could be immobilized and hybridization efficiencies up to 1.0 were reached. Hybridization efficiency was found to depend on surface density of immobilized oligonucleotides, while hybridization rates increased when MgCl2 was added. A conjugate consisting of an oligonucleotide complementary to the immobilized strand and the hexapeptide GRGDSP with RGD as an integrin recognition site was synthesized. This conjugate was able to bind to integrins on osteoblasts. It was shown that this conjugate binds to the anchor strand fixed on Ti6Al7Nb to an extent comparable with the unconjugated complementary strand.

Animals↗
PubMed2006

Oral hygiene practices, periodontal conditions, dentition status and self-reported bad mouth breath among young mothers, Tanzania.

OBJECTIVES: To determine the oral hygiene practices, periodontal conditions, dentition status and self-reported bad mouth breath (S-BMB) among young mothers. STUDY PARTICIPANTS AND METHODS: This was a cross-sectional descriptive study conducted at Muhimbili National Hospital, Dar es Salaam, Tanzania. A total of 302 postpartum mothers, aged 14-44 years, were interviewed on oral hygiene practices and S-BMB using structured questionnaire. Oral hygiene, dentition and periodontal status were assessed using the Community Periodontal Index probe and gingival recessions (GR) using Williams Periodontal probe. RESULTS: Tooth brushing practice was 99%; tongue brushing (95%), plastic toothbrush users (96%), chewing stick (1%), wooden toothpicks (76%), dental floss (<1%); and toothpaste (93%). The prevalence of plaque and gingival bleeding on probing was 100%, gum bleeding during tooth brushing (33%), calculus (99%), probing periodontal pocket depth (PPD) 4-5 mm (27%), PPD 6+ mm (3%), GR 1+ mm (27%) and tooth decay (55%). The prevalence of S-BMB was 14%; the S-BMB had higher mean number of sites with plaque compared to the no S-BMB group (P=0.04). Factors associated with S-BMB were gum bleeding on tooth brushing (OR=2.4) and PPD 6+ mm (OR=5.4). CONCLUSION: Self-reported bad mouth breath is a cause of concern among young mothers, and associated significant factors were gum bleeding on tooth brushing and deep periodontal pockets of 6+ mm. Further research involving clinical diagnosis of bad mouth breath and intervention through oral health promotion and periodontal therapy are recommended. CLINICAL RELEVANCE: This study provides baseline information on oral health status and the complaint on bad mouth breath which necessitates in the future need for objective assessment, diagnosis and management of bad mouth breath for enhanced social and professional interaction without embarrassment.

Adolescent↗
PubMed2005

[Magnetic resonance tomogography after cryotherapy of long bones in an animal model].

PURPOSE: To describe the MR findings following cryoablation of long bones. MATERIALS AND METHOD: Cryoablation was performed in femoral and tibial bones of 24 sheep under general anesthesia. MRI of the treated and untreated contralateral bones was performed immediately thereafter and at 2, 4 and 6 months after the cryosurgical procedure. RESULTS: On the MRI performed immediately after cryotherapy, the lesions showed low signal intensities relative to the normal bone marrow on unenhanced T1- and T2-weighted images. At 2, 4 and 6 months after cryoablation, the lesions showed high signal intensities on STIR images, low signal intensities on T1-weighted and heterogeneous enhancement on contrast-enhanced T1-weighted MR images. The femoral lesions decreased in size from 31 +/- 3 mm immediately after the cryotherapy to 13 +/- 4 mm 6 month later and the tibial lesions from 29 +/- 7 mm to 19 +/- 4 mm. CONCLUSION: MRI shows bone marrow lesions immediately after cryotherapy and can easily monitor healing lesions. MR imaging is suitable for following cryotherapy.

Animals↗
PubMed2004

Rate of perioperative complications in thermal ablation of bone: an animal trial.

INTRODUCTION: While only few data are available yet for radioablation of bone tissue, the occurrence of bone marrow embolisms during cryoablation has been documented. It was the aim of this study to assess perioperative complication rates of thermoablation in animals using state-of-the-art ablation probes. MATERIALS AND METHODS: Eight adult sheep were placed under general anaesthesia, and using a radioprobe, thermoablation was performed on the medial side of the head of the right tibia. In addition, freezing was performed with miniature cryoprobes on both femurs and the head of the left tibia. Haemodynamic monitoring and determination of blood gases and electrolytes were done intraoperatively. The animals were killed 1 week after surgery, and the ablation sites and lung tissue examined macroscopically and microscopically. RESULTS: None of the animals showed pathological changes in any of these parameters. Blood gases remained unremarkable throughout the operation. All eight animals showed an average drop in haemoglobin of 0.97 g/100 ml. Two animals showed fresh embolisms in the pulmonary vessels. CONCLUSION: Experimental thermoablation of bone tissue in large animals failed to show any significant perioperative complications following surgery. The lung embolisms which did occur were not clinically relevant. The use of mini-cryoprobes or radioprobes as alternative or complementary measures for treating pathologically altered bone tissue seems viable and does not involve any undue risks.

Animals↗
PubMed2004

[Changes in stability after cryosurgical treatment of long tubular bones. An animal experiment study].

The incidence of spontaneous fractures after cryosurgical treatment is described in the literature. The purpose of this study in the sheep model was to analyze the possibility of minimizing the potential risk of bone failure using a new miniature cryoprobe with minimal tissue traumatism and exact control of the ablation. In each of 24 sheep ablations at the right femur and left tibia were performed by drilling. The ablation at the femur was restricted to an area of 2 cm(2) of only one cortical bone, whereas at the proximal tibia the whole tibial plateau was included. The opposite side, which was treated with analog drillings without cryoablation, served as control. The ultimate bending strength of the femur and the ultimate compression strength of the tibia were examined 2, 4, and 6 months after the operation. After 2 months there was a significant difference ( p<0.05) in the ultimate compression strength between the treated and untreated tibiae, whereas the ultimate bending strength of the treated femora tended to be lower. After 4 and 6 months the side treated with cryosurgery was only marginally weaker than the untreated side. Spontaneous fractures were not observed during the whole experimental period. The good controllability of the freezing procedure and the low iatrogenic weakening of the bone using a modern miniature cryoprobe minimizes the risk of pathological postoperative fractures. After ablation of larger bone sections, the treated extremity should be partially unloaded or managed by osteosynthesis for at least 3 months.

Animals↗
PubMed2003

Primary intestinal posttransplant T-cell lymphoma.

There have been only five reported cases of primary posttransplant T-cell lymphoma. We report the first case associated with the use of sirolimus (Rapamycin, Wyeth-Ayerst, Philadelphia, PA). The patient, receiving prednisone, cyclosporine, and sirolimus treatment, developed ascites, diarrhea, and weight loss 7 months after his second renal transplant. Tissue obtained at laparotomy established the diagnosis of primary T-cell lymphoma. Latent membrane protein-1 for Epstein-Barr virus was negative, but in-site hybridization test for Epstein-Barr-encoded RNA was positive. Despite aggressive chemotherapy, the patient died 8 months posttransplant. This is the sixth reported case of primary intestinal posttransplant T-cell lymphoma, but it is the first case associated with the use of sirolimus. The incidence of posttransplant lymphoproliferative disease in patients receiving sirolimus should be studied.

Fatal Outcome↗
PubMed2003

[Treatment course in endoprosthetic knee replacement--a systematic insurance cost calculation exemplified by a concrete example].

In view of the planned introduction of the DRG system in Germany, this paper gives the reader a guideline on how to analyse costs and productivity of medical procedures. Total knee replacement was chosen because it is one of the standard operations in orthopedic surgery with existing special calculations for this type of operation. By using the example of a total knee replacement, productivity phases are used and their costs are estimated. With these phases the clinician is able to analyse the efficiency of his department and a benchmarking is possible. Nevertheless, we should not forget that although cost reduction in hospitals is essential the patients' health is the main aim of treatment.

Arthroplasty, Replacement, Knee↗
PubMed2003

[Results of shoulder isokinetic testing in volleyball players].

Isokinetic testing of the shoulder joint shows valuable indication to possible functional disorders and muscle imbalance. Concentric testing of several parameters using the Cybex 6000 practice unit was done by professional volleyball players performing external and internal rotation of the dominant and non-dominant shoulder at speeds of 60 degrees/s an 180 degrees/s. Sex-specific significant differences were shown which are comparable to other kind of sports.

Adult↗
PubMed2001

Unusual presentation of thoracic Pneumocystis carinii infection in a patient with acquired immunodeficiency syndrome.

Pleura-based masses and hilar adenopathy were seen on a chest radiograph of a patient with acquired immunodeficiency syndrome who had a history of Pneumocystis carinii infection. The differential diagnosis of such a presentation is discussed in light of atypical and extrapulmonary manifestations of P. carinii infection in a patient receiving prophylaxis with dapsone.

AIDS-Related Opportunistic Infections↗
PubMed2001

The Claude Bernard Distinguished Lecture. In pursuit of meaningful learning.

The Bernard Distinguished Lecturers are individuals who have a history of experience and expertise in teaching that impacts multiple levels of health science education. Dr. Joel Michael more than meets these criteria. Joel earned a BS in biology from CalTech and a PhD in physiology from MIT following which he vigorously pursued his fascination with the mammalian central nervous system under continuous National Institutes of Health funding for a 15-yr period. At the same time, he became increasingly involved in teaching physiology, with the computer being his bridge between laboratory science and classroom teaching. Soon after incorporating computers into his laboratory, he began developing computer-based learning resources for his students. Observing students using these resources to solve problems led to an interest in the learning process itself. This in turn led to a research and development program, funded by the Office of Naval Research (ONR), that applied artificial intelligence to develop smart computer tutors. The impact of problem solving on student learning became the defining theme of National Science Foundation (NSF)-supported research in health science education that gradually moved all of Dr. Michael's academic efforts from neurophysiology to physiology education by the early 1980's. More recently, Joel has been instrumental in developing and maintaining the Physiology Education Research Consortium, a group of physiology teachers from around the nation who collaborate on diverse projects designed to enhance learning of the life sciences. In addition to research in education and learning science, Dr. Michael has devoted much of his time to helping physiology teachers adopt modern approaches to helping students learn. He has organized and presented faculty development workshops at many national and international venues. The topics for these workshops have included computer-based education, active learning, problem-based learning, and the use of general models in teaching physiology.

Computer-Assisted Instruction↗
PubMed2001

The benefits of Skinner's analysis of verbal behavior for children with autism.

Behavior analysis has already contributed substantially to the treatment of children with autism, and further gains can result from more use of Skinner's analysis of language in Verbal Behavior (1957) and in the resulting conceptual and experimental work. The approach emphasizes a unit of analysis consisting of the relations between behavior, motivative and discriminative variables, and consequences. Skinner identifies seven types of verbal operants--echoic, mand, tact, intraverbal, textual, transcriptive, and copying a text--which function as components of more advanced forms of language. This approach focuses on the development of each verbal operant (rather than on words and their meanings) and on the independent training of speaker and listener repertoires. Five more specific contributions are described that relate to the importance of (a) an effective language assessment, (b) mand training in early intervention, (c) establishing operations, (d) an intraverbal repertoire, and (e) automatic reinforcement.

Autistic Disorder↗
PubMed2001

A few minor suggestions.

We agree with almost all of the analysis in this excellent presentation of the molecular view of avoidance behavior. A few suggestions are made as follows: Referring to response-generated stimuli as ''readily observable" seems not quite right for the kinesthetic components of such stimuli, although their scientific legitimacy is not questioned. Interpreting response-generated stimuli as a form of positive reinforcement is contested, and an alternative interpretation is offered. A possibly simpler interpretation of the Sidman (1962) two-lever experiment is suggested. We question Dinsmoor's (2001) explanation for warning stimuli not being avoided, except for the reference to the weakness of third-order conditioning effects. A final question is raised regarding the nature of the variables that are responsible for the momentary evocation of the avoidance response.

Animals↗
PubMed2001

Auditory function at 14 years of age of very-low-birthweight.

The aim of the study was to determine audiological function at 14 years of age of very-low-birthweight (VLBW < or = 1500 g) children compared with a cohort of normal birthweight (NBW > 2499 g) children. Participants were consecutive surviving preterm children of birthweight < 1000 g born between 1977 and 1982 (n=86) and of birthweight 1000 to 1500 g born between 1980 and 1982 (n=124) and randomly selected NBW children born between 1981 and 1982 (n=60). Audiometric tests included pure tone audiometry, tympanometry, stapedius muscle reflexes, and measures of central auditory processing. Psychometric tests included measures of IQ, academic achievement, and behaviour. There were no significant differences in rates of hearing impairment, abnormal tympanograms, figure-ground problems, or digit recall between VLBW children and NBW control children. VLBW children had higher rates of some central auditory processing problems, which in turn were associated with poorer intellectual, academic, and behavioural progress.

Adolescent↗
PubMed2001

The role of definitions in biomedical concept representation.

The Foundational Model (FM) of anatomy, developed as an anatomical enhancement of UMLS, classifies anatomical entities in a structural context. Explicit definitions have played a critical role in the establishment of FM classes. Essential structural properties that distinguish a group of anatomical entities serve as the differentiate for defining classes. These, as well as other structural attributes, are introduced as template slots in Protégé, a frame-based knowledge acquisition system, and are inherited by descendants of the class. A set of desiderata has evolved during the instantiation of the FM for formulating definitions. We contend that 1. these desiderata generalize to non-anatomical domains and 2. satisfying them in constituent vocabularies of UMLS would enhance the quality of information retrievable through UMLS.

Anatomy↗
PubMed2000

Implications and refinements of the establishing operation concept.

In this paper I discuss (a) three steps in the development of establishing operation (EO) terminology, (b) my early neglect of its possible relevance to applied behavior analysis, (c) the importance of functional analysis methodology for increasing awareness of EO issues, and (d) three comprehensive reviews that clarify the role of EOs in applied work. I then review and further analyze seven topics that require further clarification or that have been raised since my 1982 and 1993 articles: the EO evocative effect, deprivation and satiation, problem behavior maintained by attention, decreasing behavior evoked by a transitive conditioned establishing operation, EOs in the context of escape and avoidance, academic demand, and decreasing behavior evoked by a reflexive conditioned establishing operation.

Animals↗
PubMed2000

Current research on the influence of establishing operations on behavior in applied settings.

This article provides commentary on research published in the special section of the Journal of Applied Behavior Analysis devoted to establishing operations (EOs). Three major themes are highlighted: (a) identification of the influence of EOs on behavior in applied settings, (b) the use of EO manipulation as an assessment tool, and (c) the development of interventions based on the alteration of EO influences. Methodological issues pertaining to research on EOs are addressed, and suggestions for future investigation are provided.

Adult↗