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Biomedical subjects

M Anbar

Publications and source records attributed to M Anbar.

At least 19 recordsLinked to original sources
PubMed1998

The possible role of nitric oxide in the physiopathology of pain associated with temporomandibular joint disorders.

Temporomandibular joint disorders (TMD) pose a significant challenge to the practice of oral and maxillofacial surgery. When painful, TMD are generally associated with hyperthermia of the overlying skin. It is hypothesized that this skin hyperthermia, caused by regional vasodilation, is induced by nitric oxide (NO) produced in the extravascular space of the joint. Extravascular NO can be produced by osteoblasts, chondrocytes and macrophages, or by stimulated neurons. It is suggested that this kind of pain is associated with NO-enhanced sensitivity of the peripheral nociceptors. Verification and clinical implications of the proposed mechanism are discussed.

Chondrocytes↗
PubMed1998

Thermology and facial telethermography. Part I: History and technical review.

This paper is a review of historical trends and technical advances in measurement of skin temperature. Most biochemical processes generate heat which must be dissipated. Skin is the major route for heat dissipation using blood as the heat exchange fluid. Skin temperature is an indicator of aberrations in metabolism, hemodynamics or in neuronal thermoregulatory processes. Since most of the heat dissipation of skin is by infrared blackbody emission, skin temperature should be measured without contact by monitoring the emitted infrared radiation. This has been the basis of telethermography. Recent advances in computing technology combined with advanced infrared sensor technology has led to the development of dynamic area telethermometry (DAT) which promises to be as an important new quantitative method to analyse the pathophysiology of thermoregulatory processes.

Face↗
PubMed1998

Thermology and facial telethermography: Part II. Current and future clinical applications in dentistry.

Selected clinical applications using thermal imaging as an aid in dentistry are reviewed. Facial skin temperature can easily be measured in a clinical setting, without direct skin contact, by monitoring the emitted infrared radiation. This is the basis of static area telethermography (SAT) and dynamic area telethermography (DAT). SAT has recently been shown to be of help to the dentist in (1) the diagnosis of chronic orofacial pain, (2) as a unique tool in assessment of TMJ disorders, (3) as an aid in assessment of inferior alveolar nerve deficit, and (4) as a promising research tool. DAT, recently made possible by advances in computing technology combined with advanced infrared sensor technology, extracts quantitative information about hemodynamic processes from hundreds to thousands of digital thermal images of the affected facial areas, measured and collected within less than 3 min. DAT has promise of offering a better insight into aberrations of the neuronal control of facial skin perfusion and aiding our understanding of the correlation between orofacial pain and facial thermal abnormalities. This promising new insight may help in the management of orofacial pain.

Body Temperature Regulation↗
PubMed1997

Role of nitric oxide in the physiopathology of pain.

Many painful disorders, including joint dysfunctions such as rheumatoid arthritis (RA) or temporomandibular joint disorders (TMD), are associated with hyperthermia of the overlying skin. The same is true of certain intractable chronic pain conditions, such as chronic orofacial pain, which may be associated with TMD. We suggest that this skin hyperthermia, caused by regional vasodilation, is induced by extravascular nitric oxide (NO). Extravascular NO can be produced in the affected joint by osteoblasts, chondrocytes, and macrophages, by mechanical stimulation of endothelial cells, or by stimulated neurons. In view of a strong correlation between pain and skin hyperthermia in these disorders, and the evidence that NO enhances the sensitivity of peripheral nociceptors, we also suggest that at least this kind of pain is associated with excessive local level of NO. This hypothesis can be verified by dynamic area telethermometry, assessing the effect of NO on the sympathetic nervous function. This mechanism, which is in line with the general role of NO as a mediator between different organ systems, also may be relevant to any pain associated with enhanced immune response. Clinical implications of the proposed mechanism are discussed.

Humans↗
PubMed1995

Nitric oxide: a synchronizing chemical messenger.

Nitric oxide (NO) has been recognized as a ubiquitous chemical messenger in a large number of different biological systems. Its chemical properties make it less specific and less controllable than practically any other neurotransmitter or hormone. In view of this, its extensive biological role as a chemical messenger seems surprising. It is suggested that the biological function of NO evolved early in the anaerobic stage of evolution. In view of its low molecular weight, limited interaction with water, and its electrical neutrality, which allow it to diffuse rapidly through the cytoplasm and biomembranes, it is suggested that the need for NO has been retained by and maintained in eukaryote cells because of its ability to affect many biochemical functions simultaneously, acting primarily as an intracellular synchronizing chemical messenger.

Animals↗
PubMed1994

Hyperthermia of the cancerous breast: analysis of mechanism.

Cancerous breast hyperthermia is seemingly associated with non-neurological vasodilation modulated by nitric oxide (NO). NO, associated with enhanced immune response, is produced autocatalytically involving ferritin as the supplier of Fe2+, which catalyses the formation of NO. NO, in turn, releases Fe2+ from ferritin. This mechanism implies: (1) dependence of hyperthermia on the ferritin content of the neoplastic tissue; (2) oscillatory behavior of the hyperperfusion; (3) hyperthermia that extends far beyond the boundaries of the neoplastic tissue; (4) diminished neurological control of the perfusion in the affected breast; (5) limitations on the observed asymmetry between the breasts. These five effects were previously observed in numerous independent studies. Monitoring the temporal behavior of the hyperthermia is expected to substantially increase both sensitivity and specificity of cancer detection.

Body Temperature Regulation↗
PubMed1991

Comparing assessments of students' knowledge by computerized open-ended and multiple-choice tests.

At the State University of New York at Buffalo School of Medicine and Biomedical Sciences, interactive computerized tests that accept unrestricted natural-language input were used to assess the knowledge of medical students in a sophomore course on clinical biophysics in 1989. The course covered the physical bases, scopes, and limitations of the most widely used diagnostic, therapeutic, and prosthetic technologies. The test was composed of both open-ended sequential questions and multiple-choice questions on the same material. The scores for the two testing modes were correlated, paying special attention to answers that demonstrated a flagrant lack of knowledge, corroborated by subsequent answers. The correlation between the qualities of the answers for the two testing modalities was found to be significantly positive for the lower half of the class of students and negative for the upper half, suggesting that the two modes of testing measure different aspects of competence. The implications of the findings to medical education and accreditation are discussed.

Clinical Competence↗
PubMed1989

Effect of physical activity on lumbar spine and femoral neck bone densities.

The lumbar spine and femoral neck densities of 123 and 141 normal adult women (50 +/- 10 years), respectively, measured by dual photon absorptiometry, were correlated with the number of hours of walking per day associated with their regular daily activities. This measure of exercise, obtained by detailed questionnaire and interview, was analyzed because it is regular, seasonally stable, and quantifiable. Both lumbar spine and femoral neck densities were significantly correlated with walking, with 0.8% and 1.9% increases in average bone density per hour of daily walking, respectively. This increase in density is substantial, considering that the age-related rate of bone loss in the same population is 0.7% and 0.5% per year of lumbar spine and femoral neck, respectively. This means that, on the average, a woman walking one additional hour per day has a femoral neck bone density comparable to that of a women 4 years younger who does not pursue this additional activity. This physical activity-associated enhancement of bone density may be critical at old age when osteoporosis is clinically manifested.

Adult↗
PubMed1989

Normal and abnormal features of the lumbar spine observed in dual photon absorptiometry scans.

Dual photon absorptiometry (DPA) is an extensively used technique for measuring the density of the lumbar spine. The presence of vertebral and extra-vertebral pathologies can lead to increased scatter of data and artifactual bias when constructing diagnostic reference value curves. The bone density of patients with such abnormalities cannot be compared with those of normals because it will appear artificially high. Furthermore, little effort has been made to identify and evaluate spinal abnormalities using the pictograms produced in this method. We have analyzed 60 DPA scans for morphologic changes, using x-rays for comparison, and have found practically complete concurrence between these two radiologic methods on features, though only the former is capable of accurately quantifying bone density. Examples of DPA presentation of anatomical morphology are shown to aid the user in interpreting DPA findings.

Adult↗
PubMed1988

Associations of parity, breast-feeding, and birth control pills with lumbar spine and femoral neck bone densities.

The relationships between parity, breast-feeding, and the use of birth control pills and the bone densities of the lumbar spine and the femoral neck, measured by dual-photon densitometry, were studied in normal women. Femoral neck density was found to decrease by 1.1% per live-birth, whereas lumbar spine density showed no significant association with parity. Breast-feeding was found to increase lumbar spine density by 1.5% per breast-fed child, whereas femoral neck density was not significantly correlated. No significant relationships between the use of birth control pills and the bone densities were found.

Adult↗
PubMed1988

Effects of natural menopause, hysterectomy, and oophorectomy on lumbar spine and femoral neck bone densities.

Lumbar spine and femoral neck bone densities of women, aged 35-65, were measured by dual photon bone densitometry. After exclusion of women with spinal and other abnormalities, this study included 233 subjects: 60 menstruant, 91 who underwent natural menopause (56 more than 2 years post-menopause), 45 bilaterally oophorectomized, and 37 hysterectomized without bilateral oophorectomy. No significant differences were found between the age-normalized average bone densities of the menstruant, early postmenopausal, and late postmenopausal women; nor was there a difference between the rates of their bone loss. The bone densities of the hysterectomized women were significantly lower than those of the normals. The bone densities of the oophorectomized women were significantly lower than those of the hysterectomized patients. The rates of bone loss, however, were comparable in all groups studied. The use of estrogen without progestin was associated with significantly higher lumbar spine densities in the oophorectomized women, but showed no significant effect in any of the other groups.

Adult↗
PubMed1987

Computerized thermography. The emergence of a new diagnostic imaging modality.

Medical thermology is a relatively new diagnostic imaging modality that is based on thermography and has just recently gained acceptance by the medical community at large. In fact, the first comprehensive book on thermology appeared in press just a few months ago (2). Thermography is the recording and displaying of images that depict the distribution of temperature on the skin surface of patients. Thermology is the systematic interpretation of clinical thermograms. The leading thermographic technique is now based on remote infrared sensing. using digitizing techniques and microcomputers, the images can be processed to facilitate better thermological interpretation. This paper presents a brief account of the evolvement of this imaging modality, its current technology and medical uses, and its potential to become a major diagnostic tool in a large number of clinical situations. Finally, we will attempt to assess the overall role and place of thermology in medicine while also pointing out the need for fundamental thermological research to support the current empirical diagnostic applications.

Computers↗
PubMed1985

Rate of non-adherent cell loss from long-term cultures of murine bone marrow: effect of medium conditioned by the adherent cell population.

The rate of random spontaneous cell loss from the non-adherent cell population of long-term cultures of murine bone marrow was determined. The measured rate of non-adherent cell loss is affected by previous conditioning of the medium in which the non-adherent cells are suspended. Specifically, the measured rate of non-adherent cell loss is significantly slowed when the non-adherent cells are suspended in medium conditioned in long-term haematopoietic cultures instead of fresh medium. It appears that a subset of the adherent cell population is the source of the factor or factors within the medium which result in this slower measured rate of non-adherent cell loss. This effect may be due to the stimulation to division of haematopoietic progenitor cells, offsetting the lysis of other non-adherent cells.

Animals↗
PubMed1984

Effect of polyvinyl phosphonates and ethane hydroxy diphosphonate on mineralization of ectopic bone.

The effects of polymeric polyphosphonate and of ethane hydroxydiphosphonate on the development of ectopic bone were compared at different stages of bone development. The diphosphonate affected bone development at different stages, as reflected by alkaline phosphatase and aryl sulphatase activities, as well as by the creation of calcium ions by bone and on its readiness to undergo isotopic exchange. The polymeric polyphosphonate (mol. wt., 3500-8000), on the other hand, did not exhibit any of these effects, although it did inhibit the activity of the enzymes in vitro to an extent comparable with that of the diphosphonate. The results corroborate the assumption that the effects of polymeric polyphosphonates on hard tissues are confined to the extracellular space while the effects of diphosphonates on bone development are due to intracellular activity and not to sequestering of extracellular calcium.

Alkaline Phosphatase↗