Hospitalization and hospital mortality rates during the first and second waves of the COVID-19 pandemic in Quebec: interrupted time series and decomposition analysis.

OBJECTIVES: We investigated hospitalization and hospital mortality rates by cause during the first year of the COVID-19 pandemic in Quebec, Canada. STUDY DESIGN: Interrupted time series and decomposition analysis. METHODS: We analyzed hospital mortality during the first (February 25-August 22, 2020) and second waves (August 23, 2020-March 31, 2021), compared with 2019. We identified the cause of death and examined trends using: 1) interrupted time series analysis; 2) log-binomial regression; and 3) decomposition of cause-specific mortality. RESULTS: Hospitalization rates decreased; however, the proportion of deaths increased from 27.0 per 1000 in 2019 to 35.0 per 1000 in the first wave, for an excess of 8.0 deaths per 1000 admissions. COVID-19 was the cause of a third of excess deaths (2.6 per 1000). Other drivers of excess deaths included respiratory conditions (1.6 deaths per 1000), circulatory disorders (0.6 deaths per 1000), and cancer (0.9 deaths per 1000). COVID-19 was the cause of 58% of excess deaths in the second wave. Interrupted time series regression indicated that the proportion of deaths increased at the outset of the first wave but returned to prepandemic levels before increasing again in the second wave. Compared with 2019, the first wave was associated with 1.31 times (95% confidence interval [CI] 1.28-1.33) and the second wave with 1.17 times (95% CI 1.15-1.19) the risk of death during hospitalization. CONCLUSIONS: The pandemic was associated with a greater risk of hospital mortality. Excess deaths were driven by COVID-19 but also other causes, including respiratory conditions, circulatory disorders, and cancer.

Predictors and impact of postoperative atrial fibrillation following thoracic surgery: a state-of-the-art review.

This review of 19 studies (39,783 patients) of atrial fibrillation after thoracic surgery addresses the pathophysiology, incidence, and consequences of atrial fibrillation in this population, as well as its prevention and management. Interestingly, atrial fibrillation was most often identified in patients not previously known to have the disease. Rhythm control with amiodarone was the most commonly used treatment and nearly all patients were discharged in sinus rhythm. Major predictors were age; male sex; history of atrial fibrillation; congestive heart failure; left atrial enlargement; elevated brain natriuretic peptide level; and the invasiveness of procedures. Overall, patients with atrial fibrillation stayed 3 days longer in hospital. We also discuss the importance of standardising research on this subject and provide recommendations that might mitigate the impact postoperative atrial fibrillation on hospital resources.

Use of rat models to mimic alterations in iron homeostasis during human alcohol abuse and cirrhosis.

With alcoholism, there are marked disturbances in iron homeostasis that are linked to alterations in serum transferrin and ferritin concentrations. This study identifies rat models of alcohol abuse that closely mimic these disturbances. Male rats were placed in one of the following three protocols: (1) pair-feeding of liquid diets for 1-8 weeks; (2) agar-block feeding for 8 weeks; or (3) generation of cirrhosis with CCl(4). Serum samples were analyzed for ferritin, transferrin, and iron levels, and the transferrin iron saturation and ferritin/transferrin ratios were calculated. Liver iron concentrations were also determined. Serum transferrin levels were elevated in animals fed alcohol for 8 weeks in pair-feeding and agar-block feeding protocols, but reduced in rats with cirrhosis. Serum ferritin concentration was reduced in rats fed ethanol in the liquid diet, but increased in rats consuming ethanol in agar blocks, in rats pair-fed the liquid control diet, and in rats with cirrhosis. This finding was mirrored by liver nonheme iron concentrations in all experimental groups, but not in the corresponding control groups. Serum iron levels were significantly elevated only in rats fed the liquid control diet. There was a progressive decrease in transferrin iron saturation and ferritin/transferrin ratios for animals fed ethanol in the liquid diet, but not when ethanol was ingested from agar blocks. The development of cirrhosis resulted in elevated liver iron concentrations and doubled ferritin/transferrin ratios. It is concluded that these models may be used to study disturbances in iron homeostasis that occur during alcohol abuse and the (subsequent) development of liver disease.

The effect of region of interest variations on morphologic operations data and gray-level values extracted from digitized dental radiographs.

OBJECTIVE: To determine the correlations among morphologic operations (MO) values and the correlations among gray-level values for regions of interest (ROIs) placed at various locations on digital images of alveolar bone for 45 patients. STUDY DESIGN: As part of a larger study, up to 7 vertical bite-wing radiographs were taken and digitized for each of 45 patients. Sets of 2 rectangular ROIs were placed on the digitized images of interdental alveolar bone at 4 locations for each patient. The ROIs (1 crestal and 1 apical) were placed between second premolars and first molars in all 4 dental quadrants. Gray-level values were measured, and MO analysis was performed on each ROI. Descriptive statistics were calculated and correlations determined. RESULTS: Paired correlations (such as apical vs crestal, left vs right, maxillary apical vs mandibular apical) of MO values were weak (r = 0.01-0.21), but corresponding correlations for gray-level values were relatively strong (r = 0. 60-0.92). CONCLUSION: MO values varied with ROI location considerably more than did gray-level values. Additionally, ROI size and shape apparently affected MO data. Accurate placement and documentation of ROIs appear to be critical considerations in analyses that use MOs.

Morphologic operations used to distinguish between two patient populations differing in periodontal health.

OBJECTIVES: This study was conducted to determine whether morphologic operation procedures applied to digitized, non-standardized, clinical radiographs of mandibular alveolar bone could be used to distinguish between a population of patients diagnosed with periodontitis and a population of patients either diagnosed with gingivitis or having healthy gingivae. STUDY DESIGN: Two groups, one consisting of 29 patients who either had healthy gingivae or had been diagnosed with gingivitis and the other consisting of 32 patients who had been diagnosed with periodontitis, were compared. Pre-existing clinical radiographs were digitized, and for each patient three to six regions of interest were placed on an image of the mandibular posterior region of the interdental bone. The regions of interest were processed under two morphologic-operations protocols, and a mean density (referred to as an MO number) was calculated for each patient. With paired t-tests, the resulting MO numbers for the two groups were compared. RESULTS: The two populations were statistically different (p < 0.05). CONCLUSION: The results of this study indicate that morphologic operations have the potential to differentiate between patient groups differing in periodontal health.

Implant site assessment using panoramic cross-sectional tomographic imaging.

OBJECTIVES: The purpose of this study was to evaluate the ability of two different panoramic imaging systems to produce cross-sectional images with accurate vertical dimensions of the posterior mandible. STUDY DESIGN: Three partially edentulous human cadaver mandibles were used for this study. On each mandible, three potential implant sites were arbitrarily identified in an area between the mental foramen and the ascending ramus. Each site was imaged using two different panoramic machines. Using each image, the mandible's outline, cortical thickness, and position of the mandibular canal were traced on clear acetate film. The mandibles were then sectioned at each site to serve as a gold standard. The cadaver sections and tracings (corrected for magnification) were measured, recording the overall mandibular height, distance from the crest of the ridge to the superior aspect of the mandibular canal, and the thickness of the cortical bone at the most inferior aspect of the mandible. RESULTS: There were no significant differences between either of the system's image measures and the gold standard when considering the distance between the crest and the mandibular canal. Differences were noted between the systems measures and the gold standard in the assessment of the cortical bone thickness and the overall mandibular height. CONCLUSIONS: Both imaging systems can be useful for vertical measurements of a potential implant site in the posterior mandible.

The effect of image variations on fractal dimension calculations.

OBJECTIVES: We used digitized dental radiographs of alveolar bone to test the hypothesis that the fractal dimension, as calculated with the program "ImageFractal" was independent of variations in X-ray exposure, beam alignment, and region of interest placement. STUDY DESIGN: The radiographic data set consisted of 72 radiographs digitized with 200 microns pixels. Radiographs were obtained with the use of three time settings and two alignments. Rectangular regions of interest were placed on each digital image over the interdental bone between the mandibular first and second molars on six hemimandibles. Each of six hemimandibles had identical copies of a unique region of interest placed on every image in its series. New regions were made 3 months later. A fractal dimension was computed from each region of interest with the caliper method included in ImageFractal, a public domain program available through National Institutes of Health. The resulting fractal dimensions were evaluated with two repeated measures analysis of variance. RESULTS: No significant differences were found between the fractal dimensions calculated for baseline images and those from overexposed and underexposed images, from images with 4 to 6 degrees of alignment variations, or from repeat regions of interest. CONCLUSION: The results support the hypothesis that fractal dimensions derived from digitized dental radiographs are not affected by variations in exposure or small variations in alignment and imply an absolute region of interest placement may not be necessary. However, caution should be used with the use of the fractal dimension to discriminate among alveolar bone variations until further research is performed.

The effect of clenbuterol and recombinant erythropoietin on tumor growth and the anemia caused by the Walker 256 carcinosarcoma.

In patients with advanced cancer, anemia is a common complication indicative of a poor prognosis. Attempts to alleviate this have met with mixed success and interventions including erythropoietin often fail to elicit an appropriate response. We have used rats implanted with the Walker 256 carcinosarcoma as a model of non-responsive anemia. This study demonstrates that the provision of recombinant erythropoietin in the presence of clenbuterol, a beta2 agonist, attenuates both the cancer induced anemia and the growth of the tumor in this model. We hypothesize that this treatment relieves the tumor induced inhibition of hematopoiesis, which allows for not only an increase in hematocrit but an increased immunosurveillance resulting in tumor suppression.

Spatial resolution in radiometric analysis of enamel loss. A pilot study.

This pilot study was undertaken to determine whether spatial resolution affects radiometric analyses aimed at detecting progressive enamel loss. Four teeth were weighed, attached to a positioning device, and evaluated with radiography. A 1 mm strip of enamel was removed from each tooth, and the teeth were weighted again and reexamined by radiography. This process was repeated five times until 1/2 mm of dentin was removed. The radiographs were digitized twice with 59 and 200 microns pixels at 8 bits, providing two series of images with the optical densities converted into 256 gray levels. Each series of images was adjusted for contrast variation. Regions of interest were drawn on the crowns, and cumulative percent histograms (CPHs) were calculated. Within a series of CPHs enamel reduction resulted in shifts in the CPHs that were directly proportional to the amount of enamel removed. CPH shifts associated with the smaller 59 microns pixels accounted for 68% of the variation in weights caused by enamel reduction, whereas the shifts associated with the larger 200 microns pixels accounted for 50%. The results indicate that pixel size does affect radiometric determinations of enamel reduction.

Reproducibility of beam alignment using different bite-wing radiographic techniques.

Longitudinal radiographic assessment of crestal alveolar bone plays an important role in the diagnosis and long-term evaluation of periodontal disease in patients. Because practitioners use several radiographic techniques to obtain bite-wing radiographs, horizontal and vertical alignment errors could adversely affect the diagnostic impression gained from this type of radiographic examination. The objective of this study was to determine the alignment reproducibility of three different clinical techniques used to acquire bite-wing radiographs. Patients who require bite-wing radiographs as part of a dental school screening process were radiographed with modified standard bite-wing tabs and two different intraoral positioning devices. Horizontal and vertical angular deviations were measured and alignment errors were calculated for each radiograph. The mean total angular alignment error for the standard bite-wing tab technique was 6.2 degrees, whereas the mean alignment error for both positioning devices was less than 1.8 degrees. The results of this study suggest that an intraoral positioning device for acquiring bite-wing radiographs should be used.

35-mm film scanner as an intraoral dental radiograph digitizer. I: A quantitative evaluation.

A 35-mm slide scanner digital imaging system was tested for its suitability in digitizing intraoral dental radiographic film for quantitative studies. The system (Nikon model LS-3510AF Nikon Electronic Imaging, Nikon, Inc., Melville, N.Y.) uses a charge-coupled device linear photodiode array. The data content in the original film images was evaluated, and the system performance assessed objectively with the use of specially designed test films. Radiometric and geometric performances for the digitizing system were extracted from measurements and observations, and these were compared with published data for two other film digitizing systems (video camera DAGE MTI, Michigan City, Ind. and Barneyscan 35-mm film digitizer Barneyscan, Berkeley, Calif.). The techniques used to evaluate this system are easy and suitable for evaluation of any digitizing system. This scanner system (Nikon) was superior to previously evaluated systems in transforming and recording radiographic film densities across the range (0.3 to 2.0 optical density units) of clinically relevant optical densities. The scanner offers substantial advantage over the other digitizing systems for gray scale information from clinically important optical densities.

35-mm film scanner as an intraoral dental radiograph digitizer. II: Effects of brightness and contrast adjustments.

Typical 35-mm slide scanners use a photodiode array and software that allows for digital and analog controls that are manually adjustable. The digital controls provide brightness and contrast adjustments, whereas corresponding analog controls adjust the exposure time and black level that determines the clamping level of the charge-coupled device for the maximum black in the image. The objective of this study was to determine the effects of these controls on the radiometric data of intraoral dental radiograph images, to establish recommended settings, and to set specific standard guidelines for the digitization process. Three approaches were used. The results of this study demonstrate that brightness and contrast control alterations on the digitizer produces different optical densities and modulation transfer function values. The impact of these results is unresolved yet must be considered in analysis on quantitative radiometric studies.

Effect of chronic alcohol feeding on hepatic iron status and ferritin uptake by rat hepatocytes.

Alcohol abuse is known to cause disturbances to iron homeostasis in man and is associated with elevated serum ferritin levels. We have previously shown that ethanol metabolism in the rat hepatocyte is associated with an immediate reduction in ferritin uptake by this cell. In this study we have examined the effect of pair-feeding the Lieber-DeCarli liquid alcohol diet on ferritin uptake by rat hepatocytes. Rat liver ferritin was radiolabeled with 59Fe in vivo and isolated by conventional techniques. Rats were pair-fed the Lieber-DeCarli liquid alcoholic diet for 4-6 weeks. Hepatocytes, isolated from their livers by collagenase perfusion, were incubated with [59Fe]ferritin in L-15 medium at 37 degrees C and 4 degrees to measure ferritin uptake and binding. The in vitro effect of ethanol on these hepatocytes was also studied. Ferritin and iron parameters were measured in the sera and hepatocytes of these animals and a comparable group of normal chow-fed rats. The rate of ferritin uptake by hepatocytes from alcohol-fed rats was significantly faster than that of their pair-fed controls (0.743 +/- 0.061 vs. 0.540 +/- 0.042 ng/min/10(6) cells, p < 0.05). However, the rats on Lieber-DeCarli control diet exhibited a lower hepatocyte ferritin uptake rate than chow-fed animals (79.3 +/- 8.1% of the control values, p < 0.01). In vitro incubation of cells in 100 mM ethanol resulted in less inhibition of ferritin uptake by hepatocytes from alcoholic rats than from their pair-fed controls (11 +/- 7.1% inhibition vs. 43.6 +/- 10.7% for controls, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Central giant cell granuloma. Report of a case.

The central giant cell granuloma is a tumor that has great potential for the displacement of teeth and the development of a facial deformity. Although its cause and behavior are still matters for discussion, its early diagnosis and treatment are a priority. We describe a patient with a large benign central giant cell granuloma of the anterior mandible. The clinical, radiographic, and histologic appearance, as well as the appropriate treatment, are discussed in light of the current literature.

Utilization of radiographs for a state dental board examination.

A survey of 97 dentists who had recently taken a state dental board examination was completed to document the use of radiographs for the screening and treatment of their patients. The response rate was 53%. Candidates spent on average 14.25 hours screening a mean of 18 patients to identify the dental pathoses necessary to take the examination. Candidates took a mean of 28.9 (+/- 25.8) radiographs for screening purposes and during the examination with a range of 3 radiographs to a maximum of 141 radiographs. Time in practice and specialty status did not affect the total number of radiographic exposures made. The majority of radiographs taken (53%) were unlikely to be used in the direct care of the patient's dental needs. The results of this survey indicated that efforts to minimize administrative radiographs should be increased.

Iron uptake from transferrin and asialotransferrin by hepatocytes from chronically alcohol-fed rats.

Chronic alcohol intake is often associated with alterations to iron homeostasis and an increase in the serum levels of carbohydrate-deficient transferrin. As the liver is a major iron storage site and also synthesizes transferrin, the normal serum iron transport protein, the aim of this study was to test the hypothesis that these disturbances in iron homeostasis were caused by altered hepatocyte iron uptake from the abnormal transferrin. To achieve this, we have investigated iron uptake from both transferrin and asialotransferrin by hepatocytes from male Sprague-Dawley rats fed the De Carli and Lieber alcohol diet. Iron uptake from transferrin by hepatocytes from alcoholic rats was less than 60% that of control values, and in the presence of 50 mM ethanol decreased still further to 35% of the uptake by the corresponding control cells. Iron uptake from rat asialotransferrin was reduced in both groups when compared to that observed from normal transferrin; 13% by control cells and 39% by hepatocytes from alcohol-fed rats. Alcohol, however, had no further effect on asialotransferrin uptake by either hepatocytes from alcohol-fed rats, or their pair-fed controls. Transferrin binding to hepatocytes was also influenced by the alcohol diet. Although there was no difference in binding at 37 degrees C, cells from alcohol-fed rats bound 85% of this total at 4 degrees C, compared to 44% by control hepatocytes. Similar values were also obtained for hepatocyte binding of asialotransferrin; alcohol feeding resulted in an increase in binding at 4 degrees C to 73% from 58% with control cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipocyte differentiation of 3T3-L1 cells involves augmented expression of a 43-kDa plasma membrane fatty acid-binding protein.

A previously described 43-kDa plasma membrane fatty acid-binding protein (FABPPM) was not observed by immunohistochemical methods in proliferating 3T3-L1 fibroblasts. However, it was detectable in plasma membranes by the second day of confluent growth, prior to accumulation of visible lipid droplets, and was strongly expressed in 8-day differentiated adipocytes. These observations were confirmed by extraction of plasma membrane proteins and subsequent immunoblotting. Kinetics of initial [3H]oleate uptake by both fibroblasts and adipocytes consisted of the sum of a saturable and a non-saturable component. During differentiation the saturable component increased progressively. Vmax increased from 3 to 25 to 110 pmol.s-1.mg cell protein-1 between the fibroblast, the 4-day, and 8 day adipocyte stages; Km was 24 nM in fibroblasts and approximately 55 nM in both 4- and 8-day differentiated adipocytes. By contrast, the rate constant for nonsaturable oleate influx decreased progressively from 0.026 to 0.010 ml.s-1.mg protein-1 between the fibroblast and 8 day adipocyte stages. In 8-day adipocytes saturable oleate uptake was inhibited by up to 55% by antibodies against rat liver FABPPM; these antibodies had no effect on uptake of 2-deoxyglucose or the medium chain fatty acid octanoate. They also had no effect on oleate uptake by fibroblasts. These studies support the hypothesis that FABPPM is a component of a saturable transport mechanism for long chain fatty acids.

Quantitation of plasma membrane fatty acid-binding protein by enzyme dilution and monoclonal antibody based immunoassay.

A plasma membrane fatty acid-binding protein (h-FABPpm) has been isolated from rat hepatocytes. Analogous proteins have also been identified in adipocytes, jejunal enterocytes and cardiac myocytes, all cells with high transmembrane fluxes of fatty acids. These 43 kDa, highly basic (pI = 9.1) FABPpm's appear unrelated to the smaller, cytosolic FABP's (designated FABP's) identified previously in the same tissues. h-FABPpm appears closely related to the mitochondrial isoform of glutamic-oxaloacetic transaminase (mGOT), and both the purified protein and liver cell plasma membranes (LPM) possess GOT enzymatic activity. From their relative GOT specific activities it is estimated that h-FABPpm constitutes approximately 2% of LPM protein, or about 0.7 x 10(7) sites per cell. A monoclonal antibody-based competitive inhibition enzyme immunoassay (CIEIA) for h-FABPpm is described; it yields an estimate of 3.4 x 10(7) h-FABPpm sites per hepatocyte. Quantitated by either method, h-FABPpm appears to be a highly abundant protein constituent of LPM.

Plasma membrane fatty acid-binding protein and mitochondrial glutamic-oxaloacetic transaminase of rat liver are related.

The hepatic plasma membrane fatty acid-binding protein (h-FABPPM) and the mitochondrial isoenzyme of glutamic-oxaloacetic transaminase (mGOT) of rat liver have similar amino acid compositions and identical amino acid sequences for residues 3-24. Both proteins migrate with an apparent molecular mass of 43 kDa on SDS/polyacrylamide gel electrophoresis, have a similar pattern of basic charge isomers on isoelectric focusing, are eluted similarly from four different high-performance liquid chromatographic columns, have absorption maxima at 435 nm under acid conditions and 354 nm at pH 8.3, and bind oleate with a Ka approximately 1.2-1.4 x 10(7) M-1. Sinusoidally enriched liver plasma membranes and purified h-FABPPM have GOT enzymatic activity; the relative specific activities (units/mg) of the membranes and purified protein suggest that h-FABPPM constitutes 1-2% of plasma membrane protein in the rat hepatocyte. Monospecific rabbit antiserum against h-FABPPM reacts on Western blotting with mGOT, and vice versa. Antisera against both proteins produce plasma membrane immunofluorescence in rat hepatocytes and selectively inhibit the hepatocellular uptake of [3H]oleate but not that of [35S]sulfobromophthalein or [14C]taurocholate. The inhibition of oleate uptake produced by anti-h-FABPPM can be eliminated by preincubation of the antiserum with mGOT; similarly, the plasma membrane immunofluorescence produced by either antiserum can be eliminated by preincubation with the other antigen. These data suggest that h-FABPPM and mGOT are closely related.