Isoenzymes of the cytochrome P450 system: an accident or a physiologically significant concept?

The purpose of this study was to compare the Vickers Hardness (HV) of composite resin which was light-cured by 3 different light guides, either through or without a transparent polyester matrix band. The 3 light guides, standard Demetron (SG), Turbo Tip (TT) and a standard Demetron, with obvious accidental damage (DL) were tested with both Model 100 and Cure Rite radiometers. HV tests were done on all samples both immediately and one hour after light-curing. Results were analysed using the Anova and Student t-test. The light intensity readings in mW/cm2 were SG 600 and TT 850 with both radiometers and DL tested 350 and 380. Composite resin surfaces undergo significant surface hardening in the first hour after light-curing. A 350-380 mW/cm2 intensity gives significantly lower HV than 600 + mW/cm2 but 800 mW/cm2 does not produce significantly greater HV than 600 mW/cm2. Curing through a transparent polyester matrix gives marginally greater HV than curing directly. The output of light guides is a significant factor in the surface hardness of cured composite resin.     

The influence of ultraviolet radiation intensity on curing depth of photo-activated composite veneering materials

Light intensity and wavelength distribution affect post-cure properties of photo-activated composite materials. This study examined curing depth of composite veneering materials polymerized with a laboratory photo-curing unit for the purpose of evaluating the influence of ultraviolet radiation (UV) intensity on depth of cure. Three microfilled composite materials designed for prosthetic veneer were assessed. Two materials (Axis and Thermoresin LC II) were activated by both UV and visible radiation, whereas the other material (Dentacolor) was activated substantially by visible light. The light source of the photo-curing unit was a metal-halide lamp that radiates both UV and visible light. The unit was equipped with a removable UV-elimination filter capable of reducing the UV intensity from 1014.0 mW/cm2 to 574.0 mW/cm2. Each of the three materials was cured with the photo-curing unit for durations of 20, 30, 60 and 90 s both with and without the filter. The depth of cure of the materials was determined using a scraping technique described by the International Organization for Standardization (ISO 4049). Three-factor analysis of variance revealed that the depth of cure was influenced by the type of composite material, by the exposure period and also by the use of the filter (P < 0.01). Curing depth of one material (Thermoresin LC II) was significantly greater when the material was exposed without the filter than when the material was exposed through the filter. Among the three materials, the Axis composite demonstrated the greatest depth of cure regardless of exposure time period or filter use.     

Temperature rise during polymerization of light-activated resin composites

There has been a steady rise in the use of resin-based composites in the restoration of large posterior cavities. Visible light-activated materials have come to dominate the market for direct posterior composites because of the convenience offered to the operator by their command set nature. Manufacturers have produced more powerful light-activation units in response to concerns over inadequate depth of cure. However, some authors have warned of the danger to the dental pulp induced by excessive heat generated during polymerization. Variables governing heat generation include output intensity of the light-activation unit, quality of light filter, irradiation time, material composition and material surface-light guide exit window distance, residual dentine thickness and cavity dimensions. This in vitro study assessed the relative influence of some of these factors under controlled conditions. The findings suggest that minimum irradiation times should be used when curing bonding agents in unlined cavities where residual dentine thickness is limited and high output intensity light-activation units are employed. Material composition is identified as an important variable in determining the magnitude of the temperature rise.     

How different curing methods affect the degree of conversion of resin-based inlay/onlay materials

The purpose of this investigation was to measure the conversion of five inlay materials with different curing methods. In particular, the influence of secondary curing in light ovens--that is, additional curing with light and heat simultaneously--was evaluated. The conversion was determined by infrared multiple internal reflection spectroscopy. The inlays were cured with three curing methods (A, B, and C). The conversion was recorded immediately after ended curing and after an additional storage period (postcuring). The mean conversion with method A, using a handheld curing unit, was 42.1% and increased significantly to a mean of 55.4% during the storage period at (37 +/- 1) degrees C. Both curing methods B and C, including the use of light ovens, gave a mean conversion of 65%, which did not increase significantly during the storage period. This investigation demonstrated that the degree of conversion depends on the curing method used.     

Machine vision in the detection of prostate lesions in histologic sections

Post-curing properties of composite materials are influenced by the type of base monomer, activation system, filler content, and also by the type of light source employed. This study examined curing depth of four composite veneering materials polymerized by means of two different high-intensity photo-curing units for the purpose of evaluating the curing performance of the combinations of composite material and photo-curing unit. Two microfilled and two hybrid composite materials designed for prosthetic veneer were assessed. The composite materials were cured using two photo-curing units, one with a xenon light source and one with two metal halide light sources, and exposure periods varied from 20 to 90 s. Curing depth of the materials was determined with a scraping technique described by the International Organization for Standardization (ISO 4049). Three-factor analysis of variance revealed that the depth of cure was influenced by the type of composite material as well as by the photo-curing unit, and also by the exposure period (P = 0.0001). A microfilled composite material (Dentacolor) demonstrated the greatest depth of cure (4.69 mm) after 90 s irradiation with a metal halide unit (Hyper LII). Of the two photo-curing units, the metal halide curing unit consistently exhibited greater depth of cure than the xenon curing unit (Dentacolor XS). Longer exposure increased the depth of cure for all combinations.     

Indiana dentists surveyed for effectiveness of biological testing of heat sterilization units

The Indiana State Department of Health, Oral Health Services, randomly selected Indiana dentists to ascertain their compliance toward biological testing of heat sterilization units. Slightly more than 85 percent of the dentists surveyed were in compliance with the law regulating biological testing of heat sterilization units.     

Management of spinal trauma

The objective of the study was to evaluate the relationship between curing light intensity and (1) linear post-gel polymerization contraction strain, and (2) degree of conversion of a dental composite. Cylindrical specimens of a dental resin composite were cured from a distance of 7 mm for 40 s at four attenuated light intensities (71%, 49%, and 34% of control intensity and for 20 s at 71% plus 20 s at 100% intensity). A group cured at full intensity served as a control. Degree of conversion (DC) was measured at the top and bottom and linear contraction strain was measured at the bottom of the composite samples. DC at the sample top was significantly different (P < 0.05) between all groups except the 71% and 49% intensity groups. At the sample bottom, DC resulting from the two highest intensities (71% and 100%) were not significantly different from each other (P > 0.05). All other groups were significantly different from each other (P < 0.05). DC for the sample cured at two light intensities was not significantly different from those cured at the lower intensity or higher intensity for 40 s (P > 0.05). The sample cured with two intensities showed a 21.8% reduction from the contraction strain predicted by a light energy density calculation. Application of light at less than the maximum intensity of the curing light resulted in significant reduction of polymerization contraction strain without significantly affecting the degree of conversion.     

Lymphoepithelial cyst of the pancreas

OBJECTIVES: We surveyed a "population" of younger men (20 to 49 years old) for lower urinary tract symptomatology and for symptomatology associated with prostatitis. METHODS: A National Guard unit was surveyed by mail with a 58-question urinary symptom questionnaire. Surveys were returned anonymously by mail. RESULTS: International Prostate Symptom Score (IPSS) of 8 or greater was seen in 5% of men in their 20s and rose to 15% of those in their 40s. Approximately 5% (0% to 7%) reported a history of prostatitis. Caffeine caused symptoms in 2% to 13%, while exercise and smoking were not associated with symptoms. Individual prostatitis symptoms were only seen occasionally across this age group. CONCLUSIONS: As measured by the IPSS, urinary symptoms increased during the 20 to 49-year age period. A history of prostatitis in much less common than most nonpopulation studies suggest.     

Crystal Growth and Laser Characteristics of Nd3+ :KGd(WO4)2

The Nd3 3.2% (atom fraction):KGd(WO4)2 crystal was grown by Kyropoulos method. The absorption spectrum and fluorescence spectrum of Nd3 :KGW crystal were measured. The absorption cross sections at 808 nm(0.6799 ×10-20 cm2) were calculated, and the output wavelength of fluorescence is 1064 and 1351 nm. The diode-pumped laser was operated both in the free-running and passively Q-switched operating modes. The maximum laser output( 1064 nm) is 326mW with 62.7 % slope efficiency when input energy is 900 mW. The beam quality factor M2 ≈ 1.1. The green light of 532 nm is obtained in frequency doubling operation. The laser is passively Q-switched by using Cr4 :LuAG as saturable absorber. The pulse width is 170 ns at repetitive frequency of 15 kHZ.     

Age as a factor in critical care unit admissions

BACKGROUND: Although the aged occupy a high proportion of critical care beds nationwide, few multicenter studies have been undertaken to specifically determine physician attitudes toward the elderly in a critical care setting. We attempt to determine the importance of patient age as a factor in the admission of acutely ill medical patients to critical care units. METHODS: In response to a hypothetical case scenario, physicians were asked to admit one of two patients to a last available critical care unit bed. An accompanying questionnaire was used to gain a ranking of several admission factors as compared with age, and to gain demographic data regarding the study population. Data were subjected to nonparametric statistical analysis. RESULTS: When age was the only difference between two patients in a hypothetical case scenario, 80.7% of respondents chose the younger patient (age 56 years) for admission, 13.2% chose the older patient (age 82 years), and 6.2% abstained. Following the provision of more detailed medical and social information, however, only 53.5% chose the younger patient, 41.2% chose the older patient, and 5.3% continued to abstain. In a ranking of several admission factors, age was found to be of less importance than severity of presenting illness, previous medical history, and do not resuscitate status, but of more importance than patient motivation, ability to contribute to society, family support, and ability to pay for care. When asked if they supported a definitive age criterion that would restrict all patients over a certain age from access to critical care units, 95.1% responded that they did not. CONCLUSIONS: Age is a factor considered by physicians in the admission of acutely ill medical patients to critical care units. Other medical and social factors, however, can affect the impact of patient age on treatment decisions. Further study and discussion are needed to clarify the appropriate role of age and other factors in critical care unit admissions.     

Heteronymous H-reflex in temporal muscle motor units

An electric stimulation of the masseteric nerve elicits a heteronymous H-reflex in the temporal muscle. The characteristics of this reflex response were investigated by analysis of the firing probability changes of single motor units. Eleven healthy subjects participated in the experiments. The heteronymous H-reflex of the temporal muscle was electrically elicited by stimulation of the masseteric nerve at 120% of the intensity needed for the maximal masseteric M-wave. From 8 to 24 motor units were sampled from the temporal muscle of each subject. Peri-stimulus time histograms of motor unit recordings were built with a 0.5-ms bin width. The mean firing probability was calculated for the 20 ms preceding the stimulus. The firing probability was considered increased when it exceeded the mean by 3 standard deviations. Of 104 sampled motor units, 40 motor units showed a significant increase of the firing probability, which lasted 1 ms or less in 29 of them. In 12 out of 16 motor units, a significant increase of firing probability also persisted at a lower stimulation intensity (120% of the threshold needed to elicit a masseteric M wave). These data indicate that: (1) some temporal muscle motor units are modulated by afferents from the masseter muscle, (2) the heteronymous H-reflex has a monosynaptic component, and (3) there might be a more complex than just monosynaptic organization serving the heteronymous temporal H-reflex. For the latter conclusion regarding synaptic wiring, however, PSTH studies like the present one can offer only indirect evidence, and this question could be better studied in animals.     

Survey of Medicaid child dental services in Washington state: preparation for a marketing program

The authors surveyed Washington state dentists to gain an understanding of their participation in the Medicaid dental program, their willingness to learn more about the program and the degree of importance they attached to preventive care for preschool-aged children. They found that concerns about fees and administrative aspects predominated and concerns about client behaviors were expressed less often. Many dentists indicated a willingness to learn more about the program. These findings will be used to develop a plan to market the Medicaid program to Washington state dentists.     

大型空分装置安装及检修质量控制

通过对大型空分冷箱扒砂检修的诸多原因分析,结合多台空分冷箱的安装、检修、维护、运行的经验,对空分安装和检修的质量控制提出了应对措施,并在多台空分中进行了实践,效果显著。     

Age and dynamics of protein and RNA concentration in sheep oocytes]

There exists a definite age rhythm of the amount of RNA and protein in Graaf's vesicle oocytes in the postnatal life of the sheep. The lowest quantities of these components were found in the prepubertal lambs; maximum was recorded in 1,5-2,5 year ewes and later the amount of these components decreased and the oocyte of 8,5 year ewes contained 24% less general protein and 69% less RNA than 1,5-2,5 year ewes. As the oocyte grows the amounts of the protein and RNA change. A primordial follicle oocyte contains 250 +/- 15 rel. units of general protein while a Graff's follicle oocytes has three times more (767 +/- 67 rel. unit). The corresponding data for the cytoplasm RNA are: 87,5 +/- 5 rel. units and 163 +/- 18 rel. units which means a 2 times increase.     

The present state of the art in chemotherapy for soft tissue sarcomas in adults: the EORTC point of view

In the present study effects of light on the sleep duration of anesthetized hornets (Vespa orientalis) were investigated. Following initial anesthesia by diethyl ether the sleeping time of workers and drones at 22 degrees C in the dark was 59 +/- 15 min. After repeated anesthesia the sleeping time was 30 +/- 15 min in the dark. When exposed to polychromatic light from a halogen lamp of 230 mW/cm2, focused on a spot of the cuticle of the hornet, the sleeping time was markedly shortened so that following initial as well as repeated anesthesia the hornets woke up after 4.5 +/- 2.9 min. Any decrease in light intensity resulted in an increase in the sleeping time but irradiances of less than 14 mW/cm2 had no measurable influence on the wake-up time. After illumination with polychromatic light from a mercury lamp the sleeping times were much shorter than after illumination with a halogen lamp at the same conditions and intensity. This difference is attributed to the relatively higher portion of U.V. light in the total emission of the Hg lamp. Effects of the spectral composition of the incident light beam on the wake-up of the sleeping hornets were also investigated. Near U.V. light in the 300-400 nm region was found to be most efficient. Shorter wavelengths as well as wavelengths between 400-470 nm had less influence and wavelengths above 470 nm had very little effect on the wake up. The sleeping times of hibernating queens were relatively longer than those of workers and drones under the same conditions. These effects are ascribed to the extraretinal light perception. The possible reasons underlying this phenomenon are discussed.     

Who is treated in psychiatric scatter beds in general hospitals? An imputational algorithm.

We imputed where mental, alcohol, and drug disorders are treated in general hospitals (GHs). The 1980 Hospital Discharge Survey, enhanced with other information, provided data. An algorithm based on multiple discriminant analysis and clinical assumptions imputed which GH patients were treated in a psychiatric unit (PU), a chemical dependency unit (CDU), or a general medical/surgical scatter bed (SB). SBs were used much less than expected. Over 60% of GH episodes occurred in specialized sites: PUs (63%), CDUs (15%), or specialty hospitals (22%). Most SB episodes occurred in GHs with no specialized unit (75%). Patients treated in scatter beds differed systematically from those in units of the same hospital and those in hospitals with no specialized units (e.g., less psychosis and psychiatric complexity, more physical comorbidity). The de facto system of assignment of disorders to hospital sites appears rational. Implications for public policy regarding inpatient treatment are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lack of dose-response with Pancrease MT for the treatment of exocrine pancreatic insufficiency in adults

BACKGROUND: Choosing the optimum pancreatic enzyme replacement therapy for patients with exocrine insufficiency remains a problem. An enteric coated enzyme microsphere pancreatic enzyme preparation (Pancrease) has been marketed with several levels of lipase activity, implying that there is a dose-response relationship between dose and effectiveness such that the high potency form appears to be the most cost effective. METHODS: In a randomized, single-blind, cross-over study, we evaluated the effectiveness of a commercial enzyme preparation with different amounts of lipase per dosage unit in adults with exocrine pancreatic insufficiency. Patients received a diet comprising 100 g fat each day for 6 days. With each meal (three per day) they received two capsules of either Pancrease MT4 (8000 unit lipase), Pancrease MT10 (20,000 units lipase), Pancrease MT16 (32,000 units lipase) or placebo. A 72-h quantitative faecal collection was carried out for the last 3 days of the 6-day period. RESULTS: There was a reduction in faecal fat excretion with each of the preparations compared to placebo. The difference failed to reach significance with the 8000 units lipase preparation (P > 0.05) but was significant (P = 0.02) with the 20,000 units lipase and the 32,000 units lipase preparations (faecal fat excretion: placebo = 42.1 +/- 29 g, lipase 8000 = 22.1 +/- 7.3 g, lipase 20,000 = 10.2 +/- 4.5 g and lipase 32,000 = 15.8 +/- 12.5 g, P < for 20,000 units and 32,000 units lipase compared to placebo). CONCLUSION: A dose-response relationship between the amount of lipase administered with each meal and a reduction in faecal fat was not evident. The most potent preparation did not provide additional benefits compared to the less expensive lower potency dosage form.     

Medicated stainless steel ring-165, medicated gamma-intrauterine devices and TCu220C: a multicenter comparative study

PURPOSE: The purpose of this study was to compare tobacco use among high school male athletes with their nonathlete counterparts. We hypothesized that there was an inverse correlation between the intensity level of the sport and frequency of tobacco use. METHODS: Students were surveyed at seven high schools in northwest Louisiana using a 109-item questionnaire. Of the 1,200 males tested, 83% participated in one or more sports. The mean age was 15.8, and mean grade level was 10th. Sixty-seven percent were white, 27% African-American (AA), and 6% other. RESULTS: Forty-one percent of the adolescent males tested were one or more tobacco products, 31% reported cigarette smoking, 21% chewed tobacco, and 18% used snuff. Eleven percent reported using all three tobacco products. Race was a significant determinant of tobacco use, with whites being more likely to use each of the three tobacco products (P < .001). Medium- and high-intensity athletes were significantly (P < .01) less likely to be heavy smokers than athletes participating in low-intensity sports and nonathletes. However, athletes of each intensity sport used chewing tobacco and snuff at significantly higher rates (P < .001) than nonathletes. When race and grade point average were controlled, sports intensity was a significant predictor of smokeless tobacco use but not overall smoking behavior. Both AA and white high school male athletes at all sport intensity levels were using chewing tobacco and snuff at a rate higher at least 1.5 times that of their nonathlete counterparts. CONCLUSIONS: In our study, high school males' sports participation was a predictor of smokeless tobacco use but not overall smoking behavior. Although the probability of AA high school athletes using smokeless tobacco was low compared to whites, the pattern of use was similar across intensity levels of sports.     

Cat owners'' risk of acquiring a Helicobacter pylori infection

OBJECTIVES/STUDY DESIGN: A random survey of equal proportions of urban and rural North Carolina general dentists was conducted to assess their knowledge and adoption of radiographic quality assurance guidelines of the American Dental Association. RESULTS: A total of 159 surveys were returned representing a response rate of 51%. A majority of respondents answered "don't know" to questions dealing with intraoral and panoramic radiography units and darkroom monitoring. Higher levels of knowledge (58% to 77%) and adoption (63% to 86%) of guidelines were seen with film-processing activities. Linear regression demonstrated substantial positive association between knowledge and adoption of guidelines (R = 0.50). Stepwise multiple regression revealed positive associations of the demographic variables of years in practice, urban location, and age with greater knowledge of guidelines (R2 = 0.33, p < 0.05). Urban location was associated with increased likelihood of adoption of guidelines (R2 = 0.09, p < 0.05).     

Physical properties of composites cured with conventional light or argon laser

PURPOSE: To evaluate and compare diametral tensile strength (DTS), compressive strength (CS) and flexural strength (FS) of a hybrid and a microfill resin composite restorative material polymerized by an argon laser for 10 seconds (AL10) and 20 seconds (AL20) vs. a conventional visible light for 40 seconds (VL40). MATERIALS AND METHODS: Five specimens of resin composite, Herculite XRV, shade A-2 and Durafill VS, shade B-2, were made for each set of physical properties tested, for a total of 18 groups and 90 specimens. ANSI/ADA Specification #27 for direct filling resins was used as the protocol for specimen preparation and physical properties testing. An argon laser at approximately 285 mW, 6 mm beam size, power density of approximately 1,000 mW/cm2, and a conventional visible light at approximately 470 mW, 13 mm beam size, power density of approximately 354 mW/cm2, were used to polymerize the composite. Samples were stored in water in light-proof containers at 37 degrees C for at least 7 days and then tested on a Zwick universal testing machine. Mean DTS, CS or FS (MPa) values were calculated for each group. RESULTS: Herculite XRV's physical properties were not significantly affected by light source or exposure time. Light source or exposure time had no significant effect on DTS for Durafill VS. Significantly lower FS was found for Durafill VS, when cured for 10 seconds with the argon laser compared to 20 seconds with the laser or 40 seconds with the conventional light. In addition, significantly lower CS was found for the Durafill VS when polymerized with the laser at 10 seconds compared to the conventional light at 40 seconds.