Automated measurement for image distortion analysis in 2D panoramic imaging of dental CBCT system: A phantom study.

INTRODUCTION: The daily image quality assessment involves large datasets that consume a lot of time and effort. This study aims to evaluate a proposed automated calculator for image distortion analysis in 2-dimensional (2D) panoramic imaging mode for a dental cone beam computed tomography (CBCT) system in comparison with present manual calculations. METHODS: A ball phantom was scanned using panoramic mode of the Planmeca ProMax 3D Mid CBCT unit (Planmeca, Helsinki, Finland) with standard exposure settings used in clinical practice (60 kV, 2 mA, and maximum FOV). An automated calculator algorithm was developed in MATLAB platform. Two parameters associated with panoramic image distortion such as balls diameter and distance between middle and tenth balls were measured. These automated measurements were compared with manual measurement using the Planmeca Romexis and ImageJ software. RESULTS: The findings showed smaller deviation in distance difference measurements by proposed automated calculator (ranged 3.83 mm) as compared to manual measurements (ranged 5.00 for Romexis and 5.12 mm for ImageJ software). There was a significant difference (p < 0.05) on the mean measured ball diameter between automated and manual measurement. For ball diameter measurement, there is a moderate positive correlation between automated measurement with the manual measurements (r = 0.6024 and r = 0.6358 for Romexis and ImageJ, respectively). However, there is a negative correlation between automated measurement for the distance difference with manual methods (r = -0.3484 and r = -0.3494 for Romexis and ImageJ, respectively). There was a good approximation between automated and ImageJ measurement of ball diameter in comparison to reference value. CONCLUSION: In conclusion, the proposed automated calculator provides faster method with an accurate and acceptable results for daily-basis image quality test in dental panoramic mode of a Dental CBCT imaging system in comparison to current manual method. IMPLICATIONS FOR PRACTICE: An automated calculator is recommended for image distortion analysis on phantom images in routine image quality assessment for dental panoramic mode of Dental CBCT imaging system that may involve analysis of large image datasets. It offers improvement in routine image quality practice in term of time and accuracy.

[Comparison of development and mortality under domestic or institutional care with and without medical rehabilitation : The Hannover morbidity and mortality long-term care study]. / Vergleich von Pflegeverlauf und Sterblichkeit von Pflegebedürftigen mit und ohne medizinische Rehabilitation : Hannover Morbiditäts- und Mortalitätspflegestudie.

BACKGROUND AND OBJECTIVE: Empirical data, representative of the total population, are necessary for medico-actuarial risk calculations. Our study compares mortalities of long-term care (LTC) patients who are covered by statutory health insurance with regard to age and distribution of care levels when in home or institutional care with a special focus on whether rehabilitative care was performed. METHODS: The data of 88,575 LTC patients were analyzed longitudinally for 10 years, using routine data analyses on the files of the German Federal Health Insurance fund (average observation period 2.5 years, a total of 221,625 observation years). The numbers of LTC patients and their care levels while in home or institutional care were calculated, as were any changes to another care level or discontinuation of LTC benefits (as a result of the need for care falling below the eligibility criteria for care leveI or to death) during 1-10 years after the onset of LTC, always with respect to whether rehabilitative care had taken place or not. For the evaluation of care factors an indicator was developed. RESULTS: Total mortality was found to decline and reactivation to increase considerably for LTC patients after rehabilitation, basically irrespective of their age or care level and in home or institutional care settings as well. Ten years after the onset of care, 30.7 % of the patients with rehabilitation were still in nursing care, 9.8 % were reactivated and 59.5 % deceased. In contrast, only 9.2 % were still in nursing care, 3.7 % reactivated and 87.1 % deceased without rehabilitation. These results are irrespective of age distribution, care level, and residence in home or institutional care settings. The care status of patients, measured by the percentage in reactivation, care level I-III, and death, substantially depends on age at onset and care level and in addition on rehabilitative procedures. Hypotheses for further research are outlined. CONCLUSION: Rehabilitation has a clear-cut potential for life extension as well as reducing or detaining long-term care if applied to (LTC) patients. The group of rehabilitated LTC patients has a comparatively higher degree of reducing or resolving LTC up to a complete reactivation or prolonging of life in spite of care needed. A successful rehabilitative effect occurs over all age groups and all care levels during home care considerably as well as during institutional care to a lower extent. Differentiation between the age at onset of LTC, care level, and first year and follow-up mortalities is recommended as well as between rehabilitated and nonrehabilitated care patients when undertaking medico-actuarial calculations.

[Comparison of survival under domestic or institutional care: the Hannover morbidity and mortality long-term care study]. / Vergleich der Sterblichkeit Ambulanter und Stationärer Pflegepatienten im Langzeitverlauf: Hannover Morbiditäts- und Mortalitäts-Pflegestudie.

BACKGROUND AND OBJECTIVE: Empirical data, representative of the total population are necessary for medico-actuarial risk calculations. Our study compares mortalities of long-term care (LTC) patients with regard to age, gender and distribution of care levels when in home or institutional care. METHODS: The data of 88.575 long-term care patients were analysed longitudinally for ten years, using routine data on the files of the German Federal Health Insurance fund (average observation period 2.5 years, a total of 221.625 observation years). The numbers of LTC patients and their care levels while remaining in home or institutional care were calculated, as were any changes to another care level or discontinuation of long-term care benefits (as a result of the need for care falling below the eligibility criteria for care level I or to death) during 1 - 10 years after the onset of long-term care. RESULTS: Total mortality was found to increase with age and care level in homecare as well as in institutional settings for both sexes. It is greatly influenced by the first year mortality, which for both genders was lower for care level 1 in home care settings but higher for care level 2 and much higher for care level 3 than in institutional care settings. Follow-up mortality (second to tenth year after the start of LTC) was lower for care level 1 and 2 in home care settings than for institutional care. But for care level 3 the follow-up mortality was conversely higher in home care settings than in institutional care (for both genders). The number of patients returning to an active life after rehabilitation is much higher for home care patients than those who had been in institutional care. The transfer rate from homecare to institutional care increased during the first three years after onset of care, descending thereafter, and was much higher than conversely. CONCLUSION: The slogan "outpatient care before inpatient care" must be differentiated and considered carefully with regard to the character and constellation of diseases, age attained, length of time after onset of care, care level, potential for resuming an active life, as well as level of compensation and number and nature of activities of daily life together with being given the necessary help when choosing between homecare or institutional care. Differentiation between first year and follow-up mortalities is recommended when undertaking medico-actuarial calculations.

Autologous osteoblasts enhance osseointegration of porous titanium implants.

The goal of this study was to assess the osseointegration of porous titanium implants by means of coating with autologous osteoblasts. Titanium implants (8 x 5 x 4 mm) having drill channels with diameters of 400, 500, and 600 microm were coated with autologous osteoblasts obtained from spongiosa chips. The implants were inserted into the distal femora of 17 adult Chinchilla Bastard rabbits (group I). Uncoated implants were inserted as controls in the contralateral femur (group II). The animals were sacrificed after 5, 11, and 42 days. Intravital fluorochrome labeling and microradiography were used for the assessment of bone ingrowth into the titanium channels. In both groups, no bone tissue was formed in the channels up to day 5. On day 11, group I exhibited significantly more (p<0.05) bone tissue (19.8+/-14.0% vs. 5.8+/-9.1%) with greater bone-implant contact (13.3+/-15.1% vs. 5.7+/-5.3%, p<0.05) at the channel mouths than group II. Bone tissue was formed mainly between day 15 and 30 in group I, in group II between day 25 and 40. Six weeks after implantation, bone tissue filled on an average 68.8+/-15.1% of the mouths of the drill channels in implants in group I, the filling for group II was 49.8+/-18.1% (p<0.05). The average bone-implant contact at the channel mouths after six weeks was 56.5+/-13.5% in group I, 40.2+/-21.9% in group II (p<0.05). 600-microm channels showed at this time point the best osseous integration (p<0.05). Coating with autologous osteoblasts accelerates and enhances the osseointegration of titanium implants and could be a successful biotechnology for future clinical applications.

Slice culture of the olfactory bulb of Xenopus laevis tadpoles.

We report on the development of a slice culture of amphibian brain tissue. In particular, we cultured slices from Xenopus laevis tadpoles that contain the olfactory mucosae, the olfactory nerves, the olfactory bulb and the telencephalon. During 6 days in roller tubes the slices flattened, starting from 250 microm and decreasing to approximately 40 microm, corresponding to about three cell layers. Dendritic processes could be followed over distances as long as 200 microm. Neurons in the cultured slice could be recorded using the patch clamp technique and simultaneously imaged using an inverted laser scanning microscope. We characterized the main neuron types of the olfactory bulb, i.e. mitral cells and granule cells, by correlating their typical morphological features in the acute slice with the electrophysiological properties in both the acute slice and slice culture. This correlation allowed unambiguous identification of mitral cells and granule cells in the slice culture.

Noradrenergic modulation of calcium currents and synaptic transmission in the olfactory bulb of Xenopus laevis tadpoles.

Norepinephrine (NE) has various modulatory roles in both the peripheral and the central nervous systems. Here we investigate the function of the locus coeruleus efferent fibres in the olfactory bulb of Xenopus laevis tadpoles. In order to distinguish unambiguously between mitral cells and granule cells of the main olfactory bulb and the accessory olfactory bulb, we used a slice preparation. The two neuron types were distinguished on the basis of their location in the slice, their typical branching pattern and by electrophysiological criteria. At NE concentrations lower than 5 microM there was only one effect of NE upon voltage-gated conductances; NE blocked a high-voltage-activated Ca(2+)-current in mitral cells of both the main and the accessory olfactory bulbs. No such effect was observed in granule cells. The effect of NE upon mitral cell Ca(2+)-currents was mimicked by the alpha(2)-receptor agonists clonidine and alpha-methyl-NE. As a second effect, NE or clonidine blocked spontaneous synaptic activity in granule cells of both the main and the accessory olfactory bulbs. NE or clonidine also blocked the spontaneous synaptic activity in mitral cells of either olfactory bulb. The amplitude of glutamate-induced currents in granule cells was modulated neither by clonidine nor by alpha-methyl-NE. Taken together, the main effect of the noradrenergic, presynaptic, alpha(2)-receptor-mediated block of Ca(2)+-currents in mitral cells appeared to be a wide-spread disinhibition of mitral cells in the accessory olfactory bulb as well as in the main olfactory bulb.

Prevalence of self-reported health complaints among shoe workers of small workshop exposed to organic solvents in Hebron City, West Bank: a cross-sectional survey.

The study was conducted to estimate the prevalences of neurological disorders and mucous membrane irritation complaints among workers of shoe workshops in Hebron City, in particular to measure the associations between the occurrence of symptoms indicating polyneuropathy among workers and exposure to organic solvents in the glueing tasks. A group of 103 male workers from 30 workshops, exposed to organic solvents for more than one year were recruited to the study during the years 1996-1997. A validated Swedish neuropsychiatric questionnaire which contained questions on neurological and mucous irritation symptoms was used. Prevalence ratios were used as an indicator for relative risk. The overall prevalence of painful tingling of limbs (used as indicator of polyneuropathy) was high among the workshop workers (40%) and was significantly associated with long term exposure to organic solvents in glueing tasks (PR 2.8: 95% CI 1.0-8.3). Moderate associations were seen in other tasks. Headache and mental irritability did not show any association with organic solvent exposure in the workshop tasks. Breathing difficulty showed a moderate non-significant association with long term exposure to organic solvents (72 months) in cleaning tasks (1.9,0.7-4.8), while sore eyes also showed a moderate non-significant association with exposure to organic solvents for 25-72 months in the glueing tasks. Long term exposure to n-hexane (mainly found in the glues) could be the main cause of polyneuropathy among the workers of Hebron shoe workshops. The absence of effective ventilation systems and personal protective equipment might increase the prevalence of polyneuropathy among these workers. In conclusion, glues containing high concentrations of n-hexane are still in use in many shoe workshops in Hebron City (as well as in other developing countries), and long term exposure to n-hexane in glueing compounds could result in polyneuropathy among the workers. However, in the absence of objective measurements our results must be interpreted with caution. Well planned longitudinal studies with objective measures of exposure and disease are important for future research in developing countries.

A transient, RCK4-like K+ current in cultured Xenopus olfactory bulb neurons.

A transient K+ current in cultured olfactory bulb neurons of Xenopus tadpoles was studied using the whole-cell patch-clamp technique. The current, which was resistant to 80 mM tetraethylammoniumchloride (TEA) and 10 nM charybdotoxin but blocked by 5 mM 4-aminopyridine (4-AP), activated between -60 and -40 mV and showed time- and voltage-dependent inactivation. Its peak amplitude was nearly independent of the extracellular K+ concentration ([K+]o) in the range of 0.05 to 10 mM, indicating that its conductance increased upon increasing [K+]o. The transient K+ current showed a slow recovery from inactivation with the time for half-maximum recovery from a conditioning pulse to 80 mV for 1 s varying from 100 ms to 500 ms. Complete recovery required as much as 5-10 s at -80 mV, but could be speeded up at hyperpolarized potentials. The current resembles the RCK4 (Kv1.4) current of rat neurons except that its recovery from inactivation was independent of [K+]o. High-frequency stimulation (20-67 Hz) of the neurons with short (5 ms) voltage pulses resulted in a frequency-dependent, progressive inactivation of the transient K+ current. This suggests that, during phasic responses of olfactory bulb neurons, inactivation of the transient K+ current occurs and may lead to lengthening of action potentials and facilitation of synaptic transmission.