Lateral teleradiography of the cranium: the effect of head positioning in the interpretation of cephalometric tracings. An experimental study on a phantom

PURPOSE: To assess the influence of head mispositioning during lateral teleradiography of the skull for cephalometric purposes. MATERIAL AND METHODS: We used a human dry skull fixed on a professional support at a three level angular scale to quantitate lateral and anteroposterior rotations and inclinations. We took 15 radiographs at different angles (-2 degrees and -4 degrees right rotation; +2 degrees and +4 degrees left rotation; -2 degrees and -4 degrees anterior roll; +2 degrees and +4 degrees posterior roll; -2 degrees and -4 degrees right pitch; +2 degrees and +4 degrees left pitch; + 2 degrees left rotation and -2 degrees anterior roll; +2 degrees left rotation and +2 degrees left pitch). RESULTS: The analysis of the 15 radiographic tracings compared with the one obtained with the head positioned correctly showed no substantial differences in angular and linear values; no difference was such as to invalidate tracing. DISCUSSION: When skull malpositioning limited within 4 degrees, the angular and linear measurements of the cephalometric tracing are reliable and accurate. Nevertheless, cephalometric findings must always be integrated with clinical and history data. CONCLUSIONS: We believe that even less than perfect teleradiographs of the skull should be used for cephalometric purposes because, even though they require more care of the dentist to analyze them, the results are reliable and the patient is spared further X-ray exposure.     

Influence of autolysis on the quantitative cytoarchitecture of rat hepatocytes. (An ultrastructural morphometric study) (author's transl)

Introduction: Autolysis is very often a reason for cell damage and is also super-imposed on many other cell damages. Already one hour of autolysis causes serious changes in cell metabolism, which can be demonstrated morphometrically. Material and Methods: Experiments were made with 10 male adult Wistar rats. 5 animals were for control purposes and 5 animals had to undergo a 1-hour's autolysis. The morphometric analysis of the liver parenchymal cells was based on the information of Weibel et al. (1968) with the help of a computer program. Results and discussion: The consequence of the drop in energy caused by autolysis is an enlargement of the liver cell which is possibly due to a breakdown of the energy-dependent ionic pumps. One of the earliest observable cell changes is a so-called "Kernwandhyperchromatosis" and chromatin condensation within the nuclei, whereby the Kernwandhyperchromatosis is seen to be a direct consequence of the increase in lactate and decrease of pH. ATP-sufficiency causes a disturbed function of mitochondrial membranes. The microchondria are swollen, the number of mitochondrial grana is clearly reduced. An enlargement of the mitochondrial outer membrane takes place by folding while the surface of mitochondrial cristae remains unchanged. As a consequence of the altered membrane activities also the peroxisomes swell at reduced numerial density. At unchanged total volume of RER the surface of the granulated membranes of the RER decrease by 50%. This decrease caused by ribosome detachment of the granulated membranes corresponds to the enlargement of the degranulated membrane parts of the nedoplasmic reticulum. The vesiculation is caused by an unspecific damage of cytoplasm. While the density of its volume and the membrane surface remain unaltered, the SER also shows a tendency to small vesiculation caused by an unspecific damage of cytoplasm. The increase in number and volume of the lysosomes and vacuoles of unknown origin speaks for a lysosomal activity. The cell compartment responsible for protein synthesis shows the most impressive morphometric and morphologic changes, which eventually can be explained by a decrease of protein synthesis which is needed to obtain enough energy for a well operating physiological equilibrium.     

The effect of helical pitch and beam collimation on the lesion contrast and slice profile in helical CT imaging

A model is presented in this paper to describe how the contrast of a reconstructed object and slice sensitivity profile are affected by (1) the table speed or helical pitch, (2) the x-ray collimations, (3) the size of the object, (4) the alignment between the reconstructed slice and the object, (5) the distance of the object from the axis of rotation, and (6) the helical CT reconstruction algorithm employed. This contrast model is validated by both computer simulations and experiments. With this model, the contrast of a reconstructed object, slice sensitivity profile, and the longitudinal MTF can be accurately predicted. The optimal scan strategy and the point of diminishing returns can be determined prior to scanning. Several conclusions can be drawn from this model. First, overlapping reconstruction significantly improves overall scan contrast sensitivity of helical CT. Second, with a given x-ray collimation, low pitch helical scans provide better longitudinal resolutions. Third, with a given volume coverage rate (i.e., a given table speed), narrow collimation high pitch helical scans provide better longitudinal resolutions than wide collimation low pitch ones and therefore are recommended for high-contrast thin-slice applications. A lesion conspicuity model is also established.     

Pedicle instrumentation in the thoracic spine. A morphometric and cadaveric study for placement of screws

The aim of this study was to examine the possible effects of local application of a potent immunosuppressive drug, cyclosporin A (CsA), on fibroblast proliferation in vitro. Rabbit subconjunctival fibroblasts were cultured and incubated with varying doses of CsA (from 0.5 to 5%). Growth inhibition curves were obtained, and cell attachment and reversibility of drug-induced growth inhibition were studied. None of the doses stimulated fibroblast proliferation. CsA inhibited fibroblast proliferation depending on the dose and duration of application. Also, drug-induced growth inhibition decreased depending on dose and duration of application. While the dosage which led to 50% inhibition was found to be 7.2 mg/ml, 4% and higher doses had toxic effects.     

Use of peripheral quantitative computed tomography for densitometry of the femoral neck and spine in cynomolgus monkeys (Macaca fascicularis)

BACKGROUND AND METHODS: Laboratory, clinical, and epidemiologic evidence suggests that calcium may help prevent colorectal adenomas. We conducted a randomized, double-blind trial of the effect of supplementation with calcium carbonate on the recurrence of colorectal adenomas. We randomly assigned 930 subjects (mean age, 61 years; 72 percent men) with a recent history of colorectal adenomas to receive either calcium carbonate (3 g [1200 mg of elemental calcium] daily) or placebo, with follow-up colonoscopies one and four years after the qualifying examination. The primary end point was the proportion of subjects in whom at least one adenoma was detected after the first follow-up endoscopy but up to (and including) the second follow-up examination. Risk ratios for the recurrence of adenomas were adjusted for age, sex, lifetime number of adenomas before the study, clinical center, and length of the surveillance period. RESULTS: The subjects in the calcium group had a lower risk of recurrent adenomas. Among the 913 subjects who underwent at least one study colonoscopy, the adjusted risk ratio for any recurrence of adenoma with calcium as compared with placebo was 0.85 (95 percent confidence interval, 0.74 to 0.98; P=0.03). The main analysis was based on the 832 subjects (409 in the calcium group and 423 in the placebo group) who completed both follow-up examinations. At least one adenoma was diagnosed between the first and second follow-up endoscopies in 127 subjects in the calcium group (31 percent) and 159 subjects in the placebo group (38 percent); the adjusted risk ratio was 0.81 (95 percent confidence interval, 0.67 to 0.99; P=0.04). The adjusted ratio of the average number of adenomas in the calcium group to that in the placebo group was 0.76 (95 percent confidence interval, 0.60 to 0.96; P=0.02). The effect of calcium was independent of initial dietary fat and calcium intake. CONCLUSIONS: Calcium supplementation is associated with a significant - though moderate - reduction in the risk of recurrent colorectal adenomas.     

Cervical orthoses effect on cervical spine motion: roentgenographic and goniometric method of study

Movement of the cervical spine in the sagittal plane was studied in ten normal subjects from 20 to 30 years of age without and with four different cervical orthoses: (1) polyethylene Camp plastic collar with chin and occiput piece, (2) plastizote Philadelphia collar, (3) four-poster and (4) SOMI (sternal occipital mandibular immobilization). The effect of the orthoses on restricting sagittal motion was measured simultaneously using roentgenographic and bubble goniometric methods. The subject was immobilized in a straight back chair to eliminate trunk motion, and lateral cervical spine films were taken of each subject in neutral, flexion and extension without and with each orthotic device. Distortion forces exerted on the orthotic devices were standardized by measurement of pressures at the chin and occiput. Roentgenographic measurements of flexion and extension and anteroposterior displacement of the cervical spine were compared to the measurements obtained by bubble goniometry. The four-poster and SOMI were found to be most effective in restricting extension and flexion respectively. The polyethylene and plastizote orthoses were significantly less effective in restricting motion. The bubble goniometer is an adequate clinical tool in assessing overall flexion-extension of the cervical spine but is not so precise and does not give information on the degree of motion at an individual vertebral level.     

Positions of dorsal root ganglia in the cervical spine. An anatomic and clinical study

STUDY DESIGN: The authors investigated the positions of dorsal root ganglia and the relation of the location to symptoms and to the effects of nerve root infiltration in the cervical spine anatomically and clinically. OBJECTIVES: To clarify normal variation of positions of dorsal root ganglia and the relation of the location of dorsal root ganglia to symptoms and to the effects of nerve root infiltration. SUMMARY OF BACKGROUND DATA: The dorsal root ganglia of the spinal nerve has attracted much attention as an important structure in the mechanisms of radicular symptoms in the lumbar spine. Although the position of the dorsal root ganglia in the lumbar spine has been classified recently, there are few reports regarding the dorsal root ganglia in the cervical spine. METHODS: The positions of dorsal root ganglia were divided into two types: proximally situated and distally situated. The positions of dorsal root ganglia in the anatomic and clinical cases were compared. The relation of the positions of dorsal root ganglia to symptoms and to the clinical effects of nerve root infiltration were analyzed. RESULTS: There was no statistically significant difference in positions of dorsal root ganglia in C6 nerve roots between anatomic and clinical cases. In addition, there was no relation between symptoms and the positions of dorsal root ganglia in clinical cases. However, there was a significant difference in positions of dorsal root ganglia in C7 nerve roots between anatomic and clinical cases. Nerve root infiltration was significantly more effective in the distally situated type of dorsal root ganglia. CONCLUSIONS: This study defined the normal variation of the positions of dorsal root ganglia. The results strongly suggest that some attention should be paid to the position of dorsal root ganglia in the diagnosis and treatment of cervical radiculopathy.     

Clarifying the role of social comparison in the big-fish–little-pond effect (BFLPE): An integrative study.

It has been speculated that the big-fish–little-pond effect (BFLPE; the negative impact of highly selective academic settings on academic self-concept) is a consequence of invidious social comparisons experienced in higher ability schools. However, the direct role of such comparisons for the BFLPE has not heretofore been documented. The present study comprises the first evidence that the BFLPE (a) is eliminated after controlling for students’ invidious comparisons with their class and (b) coexists with the assimilative and contrastive effects of upward social comparison choices on academic self-concept. These results increase understanding of the BFLPE and offer support for integrative approaches of social comparison (selective accessibility and interpretation comparison models) in a natural setting. They also lend support for the distinction between forced and deliberate social comparisons and the usefulness of distinguishing between absolute and relative comparison-level choice in self-assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative study on the effect of osthole on proximal tibiae in ovariectomized (OVX) rats

OBJECTIVE: To determine if a correlation exists between the level of maternal serum alpha-fetoprotein (MSAFP) elevation and the rate of adverse pregnancy outcome, to examine the timing of pregnancies ending in fetal or neonatal death, and to develop a protocol for antepartum surveillance in an effort to prevent these adverse outcomes. STUDY DESIGN: Singleton pregnancies with a single second-trimester elevated MSAFP > or = 2.0 multiples of the median (MoM) were eligible if a targeted ultrasound evaluation (< 24 weeks) was in agreement with the dates and no fetoplacental anomaly was detected. Three groups were established based on the second-trimester MSAFP elevation: 2.0-2.49, 2.5-2.99 and > or = 3.0 MoM. RESULTS: Among the 383 patients enrolled, delivery data were available on 333 infants. Stratified by MSAFP elevations of 2.0-2.49, 2.5-2.99 and > or = 3.0 MoM, the rates of adverse pregnancy outcome were: (1) preterm birth: 14.3%, 15.6%, 20.3%; (2) small for gestational age at birth: 7.4%, 11.1%, 22.2%; and (3) perinatal deaths (neonatal and fetal): 2.6%, 3.3%, 5.6%. Seven pregnancy losses (three neonatal and four fetal deaths) occurred prior to 28 weeks. Of these seven, six fetuses exhibited intrauterine growth retardation by 23-26 weeks' gestation, and five of six were associated with MSAFP levels > or = 2.5 MoM. Four losses (two neonatal and two fetal deaths) occurred after 28 weeks. Of these, three involved structurally normal infants with normal growth who died after 34 weeks. All three of these pregnancies exhibited MSAFP elevations < 2.5 MoM. CONCLUSION: In pregnancies with an unexplained elevated second-trimester MSAFP, the rate of adverse pregnancy outcomes is increased with higher elevations. Any proposed program to improve pregnancy outcome in patients with unexplained MSAFP elevations must include efforts aimed at preventing preterm delivery, repeat ultrasound at 24-26 weeks to rule out early-onset intrauterine growth retardation in pregnancies with elevations > or = 2.5 MoM and fetal biophysical monitoring, even in normally grown fetuses, instituted at 32 weeks to detect fetuses at risk for intrauterine death.     

Neurotoxicity evoked by N-methyl-D-aspartate in the organotypic static slice cultures of rat cerebral cortices: effect of GABA(A) receptor activation

BACKGROUND: von Recklinghausen's neurofibromatosis is a hereditary disease that may affect any organ or system of the body primarily or secondarily, including the vascular system. Among the rare cerebrovascular abnormalities, the most common is stenosis or occlusion of the cerebral artery. Intracranial aneurysms are uncommon. CASE DESCRIPTION: A case of an intracranial cerebral aneurysm associated with von Recklinghausen's neurofibromatosis is reported. A 55-year-old woman presented with a history of intermittent headache for 2 months and right oculomotor nerve palsy for 1 month. Widespread cutaneous neurofibromas and angiomas were found over her trunk and limbs with prominent cafe-au-lait spots. X-ray showed that her left lung was compressed by a large mass in the left chest with rib defects and lateral spinal curvature. Right internal carotid angiography revealed a saccular aneurysm between C1 and C2. Craniotomy to clip the aneurysm could not be performed because the mass in her chest made intubation for general anaesthesia almost impossible. CONCLUSION: The clinical features of this case are discussed together with a review of 15 similar cases in the literature. There are different theories about this disorder. We agree that the malformations are derived not only from ectodermal, but also from mesodermal pathology. In terms of our case, we consider the progression of this disease to be slow.     

A comparative study on the effect of three methods of instrumentation on the shape of root canal (an in-vitro study)

This study compared the ability of three types of engine driven instrumentation techniques to negotiate and prepare small, slightly curved root canals. Forty five mesial roots of extracted maxillary and mandibular first permanent molars were classified into three groups. Group (I) was prepared by Canal Leader system, group (II) was prepared by Nickel Titanium files and group (III) was prepared by Canal Master technique. Radiographs of the root canal space before and after preparation was carried out by the aid of an experimental model. Enlarged photographic prints obtained from radiographs were scored for shaping effectiveness of the three techniques in respect to canal course, position & width of apical constriction and lack of ledge formation. The results indicated that the Canal Leader system was an efficient technique in maintaining canal curvature, absence of zipping, transportation or ledge formation in almost all of the specimen tested, followed by the Nickel Titanium files and then the Canal Master technique which produced more straightening and destruction of apical constriction.     

Dynamics of the activity of energy metabolism and lysosomal enzymes in experimental atherosclerosis (a quantitative histochemical study)

A quantitative biochemical study of patterns of energy and lysosomic enzymes in cellular elements of the rabbit aorta under induced atherosclerosis showed these enzymes to be activated during earlier atherogenetic stages associated with the formation of atherosclerotic patches in the intima, an evidence of functional adaptation of the aortal wall building up the defence mechanisms against adversary effects of cholesterol and other lipids. Once marked atherosclerotic patches have been formed in the aorta, adaptive potentials of enzyme systems are exhausted and further changes in their activity can result in processes conducive to the development of experimental atherosclerosis.     

The effect of prostatilen on the hemostatic indices in chronic prostatitis (a clinical and experimental study)

Continuous monitoring of dynamic changes of transcranial regional cerebral oxygenation (rSO2) was performed in 7 healthy volunteers (mean age 40.9 +/- 12.6 years; range 25-62 years) during normo- and hyperbaric oxygenation (HBO at 2.5 and at 1.95 ATA) using an INVOS 3100 cerebral oximeter. A significant change between HBO and control phase could be found in rSO2, alterations (p < 0.05; ANOVA, Tukey test). The results suggest that the calculation of rSO2 may be a useful method to monitor changes of oxygen saturation under hyperbaric conditions. However, the absolute quantification of rSO2 is useless at the moment and needs further investigation.     

An inertia effect (resistance to change) in the revision of opinion.

Earlier studies have reported a reluctance of Ss to reduce their confidence in a decision following disconfirming information. This inertia effect may be due to a commitment process, or to the fact that Ss expect some disconfirming information to occur. To test the commitment hypothesis, 5 groups of Ss, with 15 male undergraduates each, were run in a sequential decision-making task, under conditions of varying levels of commitment to preliminary confidence judgments. An inertia effect, measured directly, or through an increase in confidence as a function of sample size, was present in Ss who gave confidence judgments that were displayed or could easily be recalled. In other Ss the effect was absent. It is concluded that the inertia effect was the result of Ss' commitment to their initial judgments. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of a cardiac rehabilitation program on the joints and spine: subjective evaluation

This study was designed to evaluate the effect of selective photothermolysis on dark pigmented hair follicles treated with a normal-mode ruby laser (694-nm wavelength, pulse duration 0.5 ms, fluence 20 J/cm2, spot size 2 mm). In 15 volunteers, four test areas each were selected. After shaving, the first area was irradiated once, the second twice, the third three times and the fourth served as control area. A punch biopsy was taken from each volunteer immediately after the first laser treatment. Four weeks after the last irradiation, no effect was found in six cases and little effect in another six cases (50-90% regrowth). Hair regrowth of less than 30% was observed in only three cases. Eight weeks after the last session, no effect was found in 11 cases, little effect in 2 cases (10%) and less than 30% regrowth in only 2 cases. Twelve weeks after the last treatment, no difference could be detected between the areas untreated and treated by laser. The laser parameters applied in this study do not result in effective epilation of body hair. In some cases, a delay in growth of several weeks was noticed.