Subtraction radiography and computer assisted densitometric analyses of standardized radiographs. A comparison study with 125I absorptiometry.
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Biomedical subjects
Publications and source records attributed to E Hausmann.
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Subtraction radiography, a sensitive and accurate technique for identifying alveolar crestal change from standardized pairs of radiographs, is useful in monitoring periodontal therapy. One half of the radiographs were found to be appropriate for subtraction analysis using present technology for taking standardized radiographs. The criterion for usability was identical interpretation of subtraction images made in duplicate from a pair of radiographs. A set of radiographs was analyzed by subtraction radiography as well as by measurement of alveolar bone-crest height. Subtraction radiography was found to be more sensitive in detecting change. Whereas 53% pairs of radiographs showed a change on subtraction radiography, only 14% showed a change in crest height. Comparison of change by subtraction radiography and probing attachment level showed an overall correlation. Since these two measures assess different aspects of the periodontium, perfect correlation was not expected.
A fatal monointoxication with diphenhydramine in a male 28 year old is reported. The patient went into hyperpyrexia and tachycardia and died from sudden cardiac arrest. Hemorrhagic pulmonary edema and renal shock were the most prominent pathomorphological findings. At the time of death, the concentration of diphenhydramine was 5 mg/l plasma and was particularly high in the lungs (55 mg/kg) and kidneys (50 mg/kg).
The binding of prostaglandin E2 (PGE2) to bone cells was studied to provide direct evidence for the existence of specific receptors in bone. Bone cells were isolated by collagenase digestion of fetal and newborn rat calvaria. Isolated cells were incubated with 3H-PGE2 and collected on Millipore filters. Specific binding was determined by subtracting the binding that occurred with 10(-6) M non-radioactive PGE2 and 3H-PGE2 from that with 3H-PGE2 alone. With heterogeneous cell preparations and at PGE2 concentrations from 10(-9) - 1.7 X 10(-8) M at 37 degrees C, specific binding reached steady state within 10 min. Bound 3H-PGE2 was displaced by the addition of increasing amounts of unlabeled PGE2. Inhibition of PGE2 binding was observed with PGE1 and the endoperoxide analog, U44069, but not with PGF2 alpha, a lipopolysaccharide, or 13,14-dihydro 15-keto PGE2. Studies with bone cell populations, obtained by sequential digestions, indicated that an osteoclastic population binds 30-fold more PGE2 than osteoblastic cells. Scatchard analyses revealed that the osteoclastic cells have an affinity constant for PGE2 binding similar to that obtained with heterogeneous populations. However, the PGE2 binding capacity in this osteoclastic population was fivefold greater than in the heterogeneous population. The osteoclastic population responded with an increase in cyclic AMP to lower concentrations of PGE2 than the osteoblastic populations. These studies suggest that differences in the binding capacity of PGE2 receptors exist among bone cell-types and that these differences are reflected in the cellular cyclic AMP response.
In a prospective randomized study, 60 outpatients received 0.8%, 1.5% or 2% prilocaine (4 mg/kg body weight) as i.v. regional anaesthesia for operations in the carpal region. The latent period, quality and duration of analgesia after release of the tourniquet were analysed. The latent period was shortest with 2% prilocaine. The duration of analgesia after tourniquet release increased from 5.7 min with 0.8% to 15.6 min with 2% prilocaine. The plasma concentrations after 1.5% prilocaine were significantly less than with 0.8% prilocaine.
No practical methods are presently available for measurement of alveolar bone activity at one instant of time. However, roentgenological methods making measurements at 2 different times can be used to assess alveolar bone activity. The most sensitive, specific and accurate method for this purpose presently in use is 125I absorptiometry. This method has the further advantage of giving the patient minimal radiation exposure. New methodology is under development which obviates the need for fixed geometry and could provide a 3-dimensional image of alveolar bone.
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The EMIT-dau for methadone and the EMIT-ST for opiates (both EMITs from Syva-Merck) gave false-positive results when applied to urine samples of a patient suffering from a moderate doxylamine monointoxication. The error was not detected in routine TLC. Gas chromatography and mass spectrometry unequivocally indicated the presence in urine and plasma of doxylamine and its metabolites and the definite absence of methadone. Opiates could not be detected with the Abuscreen RIA (Roche), which is a more sensitive method than EMIT-ST.
In a prospective randomised study, 20 out-patients in each group received 0.8%, 1.5% or 2% prilocaine (4 mg/kg body weight) as intravenous regional anaesthesia for operations in the carpal region. The latency time, quality of analgesia and recurrence of pain after the tourniquet release rose with increasing prilocaine concentration from 5.7 min on average at 0.8% to 15.6 min on average at 2%. The latency time was shortest with 2% prilocaine. The blood plasma levels using the highly concentrated prilocaine were significantly lower than with 0.8% prilocaine.
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Synthetic N-acetyl-muramyl-L-alanyl-D-isoglutamine (MDP) stimulated the release of 45Ca from fetal rat long bones in culture for 48 h and also increased the number of osteoclasts per bone and the number of nuclei per osteoclast. It also increased calcium uptake in enriched populations of osteoclasts obtained by sequential collagenase digestions of newborn rat calvaria. This effect was observed after a 120 min incubation with 10(-6) M MDP. Effects of MDP on calcium uptake in osteoblasts were not consistently observed. No effects on cyclic AMP were noted in either osteoclast or osteoblast populations treated with MDP for periods from 1-120 min at 37 degrees C.
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PREVIOUS STUDIES have shown that 125I absorptiometry gives an accurate and sensitive measure of alveolar bone mass. The purpose of this study was to determine the relationship between alveolar bone mass determined by 125I absorptiometry and bone density obtained by analysis of standardized intraoral radiographs by the Magiscan System. A defect of increasing size was made at one site of the alveolar bone in a human skull. The amount of bone remaining at each step was calculated using 125I absorptiometry. Standardized radiographs were also taken at each step and the relative density in the area of the defect was determined by the Magiscan System. The Magiscan's System Computer Memory permits analysis of identical areas on a longitudinal series of films of the same alveolar bone location. The results indicate that in estimating amounts of alveolar bone the Magiscan analysis of standardized intraoral radiography is similar in sensitivity and accuracy to 125I absorptiometry.
THE BJORN TECHNIQUE is widely used in periodontal studies as a standardized measure of alveolar bone. Recent studies have demonstrated the feasibility of using 125I absorptiometry to measure bone mass. The purpose of this study was to compare 125I absorptiometry with the Bjorn technique in detecting small sequential losses of alveolary bone. Four periodontal-like defects of incrementally increasing size were produced in alveolar bone in the posterior segment of the maxilla of a human skull. An attempt was made to sequentially reduce the amount of bone in 10% increments until no bone remained, a through and through defect. The bone remaining at each step was measured using 125I absorptiometry. At each site the 125I absorptiometry measurements were made at the same location by fixing the photon source to a prefabricated precision-made occlusal splint. This site was just beneath the crest and midway between the borders of two adjacent teeth. Bone loss was also determined by the Bjorn technique. Standardized intraoral films were taken using a custom-fitted acrylic clutch, and bone measurements were made from the root apex to coronal height of the lamina dura. A comparison of the data indicates that: (1) in early bone loss, less than 30%, the Bjorn technique underestimates the amount of loss, and (2) in advanced bone loss, more than 60% the Bjorn technique overestimates it.
In a prospective randomized study plasma levels of prilocaine and bupivacaine were analyzed after intravenous regional analgesia (IVRA). 20 patients respectively received either 1 mg/kg bupivacaine or 4 mg/kg prilocaine in an equipotent dosis. Prilocaine proved to be significantly less toxic than bupivacaine. Plasma levels of bupivacaine, expressed as percentage of the toxic limit, were threefold higher than those of prilocaine. In one case the maximum level of bupivacaine reached even 85% of the toxic limit. This demonstrates the possibility of dangerous side effects when exceeding the bupivacaine dose of 1 mg/kg. Methaemoglobin formation following use of prilocaine was of no clinical importance. Prilocaine is the agent of choice for intravenous regional analgesia. The use of bupivacaine for IVRA should be limited to special indications.
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The mechanism by which diphosphonates inhibit bone resorption remains speculative; however, the osteoclast appears to be selectively affected by the drug. This study examined the effects off diphosphonate on osteoclasis in bones treated concomitantly with agents which reduce the osteoclast ruffled border, calcitonin and colchicine. Dichloromethylene diphosphonate, calcitonin, and colchicine inhibited parathyroid-hormone-stimulated bone resorption, as indicated by a significantly reduced release of 45Ca from prelabelled long bones. Quantitative and qualitative histological analyses of osteoclasts indicated differences among effects resulting from agents. Only bones treated with diphosphonate demonstrated a majority of osteoclasts with degenerative appearance; colchicine-treated bones exhibited many spherulated cells with cytoplasmic blebs. The number of normal osteoclasts in calcitonin-treated bones was the same as in controls and decreased with diphosphonate and colchicine treatment. All inhibitory agents reduced the number of nuclei per osteoclast; furthermore, colchicine effected an additional significant reduction, as compared with diphosphonate and calcitonin. The number and frequency of abnormal osteoclasts was increased by diphosphonate, but unaffected by colchicine and calcitonin. The addition of calcitonin, but not colchicine, to diphosphonate-treated bones decreased the incidence of abnormal osteoclasts. Although both calcitonin and colchicine are known to reduce the osteoclast ruffled border, this study has shown differences between the morphological effects of the 2 agents which presumably reflect differences in their mode of action and their interaction with diphosphonate.