Accuracy and repeatability of blood volume measurement by pulse dye densitometry compared to the conventional method using 51Cr-labeled red blood cells

OBJECTIVE: To determine the accuracy and repeatability of pulse dye densitometry (PDD) in measuring blood volume (BV) by comparing it with the conventional method using 51Cr-labeled red blood cells (RI method) and by assessing sequential measurements. DESIGN: Prospective clinical study. SETTING: University hospital. PATIENTS AND PARTICIPANTS: Eleven adult ICU patients who received cardiac surgery (1st ICU day). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: After injecting indocyanine green (10 or 20 mg) into the right atrium, its arterial concentration was continuously monitored at the nose and finger by PDD, and BV was calculated by back extrapolating the logarithmic dye concentration on the dye elimination curve between 2.5 and 5.5 min after mean transit time to each mean transit time with the least squares method. These measurements were repeated in eight patients and performed only once in the other three, and the BV was measured concurrently by the RI method one time. The Bland-Altman method was used for evaluating differences between methods and within methods. The (percentage) biases and standard deviations between the PDD and RI methods and between the successive measurements by PDD at the finger and nose were 0.26 +/- 0.491 (8.8 +/- 15.3%) and 0.004 +/- 0.251 (0.06 +/- 5.9%) with the probe on a nostril, and 0.16 +/- 0.561 (2.5 +/- 14.4%) and 0.19 +/- 0.311 (4.7 +/- 7.3%) using the finger probe. The bias between methods was less than 10%, and the repeatability of PDD was better. CONCLUSIONS: As PDD can measure BV with good repeatability and with a small bias compared to the RI method, serial changes in BV can be evaluated at the bedside of critically ill patients noninvasively and repeatedly.     

Influence of different beverages on the force degradation of intermaxillary elastics: an in vitro study

Objective:

The aim of this study was to evaluate in vitro the effects of frequently ingested beverages on force degradation of intermaxillary elastics.

Material and Methods:

One hundred and eighty 1/4-inch intermaxillary elastics (TP Orthodontics) were immersed into six different beverages: (1) Coca-Cola^®; (2) Beer; (3) Orange juice; (4) Red wine; (5) Coffee and (6) artificial saliva (control). The period of immersion was 15 min for the first and second cycles and 30 min for the third to fifth cycles. Tensile forces were read in a tensile testing machine before and after the five immersion cycles. One-way repeated measures ANOVA was used to identify significant differences.

Results:

Force degradation was seen in all evaluated groups and at all observation periods (p<0.05). A greater degree of degradation was present at the initial periods, decreasing gradually over time. However, no statistically significant differences were seen among groups at the same periods, showing that different groups behaved similarly.

Conclusion:

The chemical nature of the evaluated beverages was not able to influence the degree of force degradation at all observation periods.     

Role of SIBLINGs on matrix mineralization: Focus on dentin matrix protein 1 (DMP1)

Dentin matrix protein 1 (DMP1) is a member of the SIBLING (Small Integrin-Binding Ligand, N-linked Glycoprotein) family of genetically related noncollagenous proteins in mineralized tissues. DMP1 was originally postulated to be dentin-specific, but its expression was later found to be present predominantly in osteocyte of bone. A unique feature of DMP1 is its unusually large number of acidic domains. Because of its highly acidic nature, DMP1 can bind to calcium, thereby regulating matrix mineralization. Protein chemistry analysis showed that full-length DMP1 is a precursor that is cleaved into NH₂-terminal 37-kDa and COOH-terminal 57-kDa fragments. Functional analyses demonstrated that the COOH-terminal 57-kDa fragment of DMP1 is essential for mineralization and maturation of osteoblast to osteocyte. The phenotype of DMP1-null mice with hypophosphatemia led to the discovery of DMP1 mutations in autosomal-recessive hypophosphatemic rickets (ARHR). Both DMP1-null mice and individuals with ARHR exhibit elevated serum FGF23 that causes increased renal phosphate wasting, leading to hypophosphatemia. These findings indicate that regulation of matrix mineralization by DMP1 is coupled to renal phosphate homeostasis through FGF23 production by osteocyte. This review summarizes the current understanding of DMP1 focusing on bone formation and homeostasis.     

Evaluation of a hybrid artificial liver module based on a spheroid culture system of embryonic stem cell-derived hepatic cells

Hybrid artificial liver (HAL) is an extracorporeal circulation system comprised of a bioreactor containing immobilized functional liver cells. It is expected to not only serve as a temporary liver function support system, but also to accelerate liver regeneration in recovery from hepatic failure. One of the most difficult problems in developing a hybrid artificial liver is obtaining an adequate cell source. In this study, we attempt to differentiate embryonic stem (ES) cells by hepatic lineage using a polyurethane foam (PUF)/spheroid culture in which the cultured cells spontaneously form spherical multicellular aggregates (spheroids) in the pores of the PUF. We also demonstrate the feasibility of the PUF-HAL system by comparing ES cells to primary hepatocytes in in vitro and ex vivo experiments. Mouse ES cells formed multicellular spheroids in the pores of PUF. ES cells expressed liver-specific functions (ammonia removal and albumin secretion) after treatment with the differentiation-promoting agent, sodium butyrate (SB). We designed a PUF-HAL module comprised of a cylindrical PUF block with many medium-flow capillaries for hepatic differentiation of ES cells. The PUF-HAL module cells expressed ammonia removal and albumin secretion functions after 2 weeks of SB culture. Because of high proliferative activity of ES cells and high cell density, the maximum expression level of albumin secretion function per unit volume of module was comparable to that seen in primary mouse hepatocyte culture. In the animal experiments with rats, the PUF-HAL differentiating ES cells appeared to partially contribute to recovery from liver failure. This outcome indicates that the PUF module containing differentiating ES cells may be a useful biocomponent of a hybrid artificial liver support system.     

Occupational Exposure to N,N-Dimethylformamide in the Summer and Winter

We evaluated total body burden of N,N-dimethylformamide (DMF) taken through the lung and skin by personal exposure of workers to DMF and urinalysis of N-methylformamide (NMF) and N-acetyl-S(N-methylcarbamoyl)-cysteine (AMCC). A total of 270 workers were engaged in four different jobs in a workplace distant from main production lines emanating high levels of DMF. They were not required to wear any personal protective equipment including respirators or gloves. We found that log-transformed urinary levels of NMF and AMCC increased with an increase in log-transformed concentrations of exposure to DMF. Urinary levels of NMF and AMCC were significantly higher in the summer than the winter, although there was no significant seasonal difference in the concentrations of exposure to DMF. Our findings suggested that the increased urinary levels of NMF and AMCC in the summer resulted in increased skin absorption of DMF due to an increased amount of DMF absorbed by the moisturized skin under humid and hot conditions. Seasonal changes in the relative internal exposure index confirmed the present finding of enhanced summertime skin absorption of DMF. AMCC is thought to be a useful biomarker for assessments of cumulative exposure to DMF over a workweek and for evaluations of workers’ health effects.     

Effect of total arthroplasty combined with anti-tumor necrosis factor agents in attenuating systemic disease activity in patients with rheumatoid arthritis

We assessed the effect of total large-joint arthroplasty combined with anti-tumor necrosis factor (TNF) therapy for rheumatoid arthritis (RA). We studied 45 RA patients (age 57.91 ± 12.74 years, RA duration 13.43 ± 8.28 years) who underwent total arthroplasty (35 knees, 19 hips, 3 elbows, and 1 ankle) between August 2002 and November 2009. All patients received anti-TNF agents (infliximab, 22; etanercept, 33; adalimumab, 3) during the period of the study (that is, they were being treated with the agents when operated on and postoperatively). The disease activity score 28 (DAS28)-erythrocyte sedimentation rate (mean ± standard deviation) in all patients improved significantly from baseline (just before the operation; 4.32 ± 0.99) to 1 year after the operation (3.35 ± 0.93) in contrast with the finding that the mean DAS28-ESR values had remained unchanged from 1 year before the operation to the baseline. Changes in clinical variables in the 58 cases were investigated at baseline, and at 4, 12, and 52 weeks after the operation. The patients were divided by a median split of baseline demographics into 2 groups for further evaluation. Compared with the high-value groups, those with low C-reactive protein and matrix metalloproteinase-3 values showed better results and had lower disease activity. Overall, the DAS28-ESR in both groups had improved 1 year after the operation. In RA patients who are being treated with anti-TNF agents, large-joint arthroplasty may be beneficial, not only for the relief of pain arising from joint destruction, but also for the systemic reduction of RA activity.     

Intra-gastric pH following single oral administrations of rabeprazole and esomeprazole: double-blind cross-over comparison

Comparisons between the acid inhibitory effects of rabeprazole and esomeprazole after single oral administration with standard doses have not been previously presented. We examined intra-gastric pH after oral administrations of these two proton pump inhibitors using 24-h pH monitoring. Fifty-four normal volunteers not infected by Helicobacter pylori were investigated. Using a cross-over design, we administered 10 mg of rabeprazole or 20 mg of esomeprazole in 27 at 30 min after supper and in the remaining 27 subjects at 15 min before supper, and performed 24-h pH monitoring. Intra-gastric pH data were nearly identical when the proton pump inhibitors were taken after meals. Even if the data were compared in different CYP2C19 genotypes, rabeprazole and esomeprazole did not show the difference. In poor metabolizer, both of the drugs showed stronger acid inhibition. When taken before meals, intra-gastric pH after esomeprazole administration was slightly but not significantly higher than that observed after rabeprazole administration not only in daytime but also in nighttime period. In conclusion, rabeprazole and esomeprazole were similarly effective when administered after a meal.