Enamel Matrix Derivative, 58S5 Bioactive Glass, and Fluoride Varnish for Enamel Remineralization: A Multi-analysis Approach.

PURPOSE: This study aimed to evaluate the enamel remineralization efficacy of enamel matrix derivative (EMD), experimental bioactive glass (BAG), and fluoride varnish in vitro. METHODS AND MATERIALS: Artificial initial caries lesions were developed on fifty human enamel specimens using demineralization solution (pH 4.5, 37°C, 96 hours). Specimens were randomly assigned to five groups (n=10): I-5% NaF varnish (Enamelast), II-experimental 58S5 BAG+37% phosphoric acid (PA), III-EMD (Emdogain) + Ethylenediaminetetraacetic Acid (EDTA), IV-EMD+37% PA, V-Control (untreated). All remineralization agents were applied with pH cycling for seven days. The specimens were scanned by spectral domain optical coherence tomography (SD-OCT) at baseline, at demineralization, and after pH cycling. Lesion depths were measured using image analysis software (ImageJ). Lesions were evaluated using surface microhardness (SMH) and two fluorescence methods (FluoreCam and DIAGNOdent Pen [DDPen]). The data were statistically analyzed by Kruskal Wallis, Friedman, and Wilcoxon tests (α=0.05). RESULTS: According to SD-OCT results, fluoride varnish was found to be the most effective agent in reducing lesion depth (p=0.005). All agents increased the SMH values after pH cycling. No significant difference was found among fluoride varnish, BAG, and EMD+PA groups. These SMH values were significantly higher than EMD+EDTA and control groups (p<0.001). All groups showed lower DDPen scores compared with the control group (p<0.001), however, no significant difference was found among the remineralization agents. In FluoreCam assessment, size and intensity values of all treated groups showed improvement. However, there was no significant difference between the treatment groups in terms of FluoreCam size measurements (p=0.186). CONCLUSION: 58S5 BAG and EMD+PA have remineralization capacity as effective as fluoride varnish. EMD+PA showed better SMH and lesion intensity results than EMD+EDTA.

Effects of Gundelia tournefortii L. on biochemical parameters, antioxidant activities and DNA damage in a rat model of experimental obesity / Efeitos de Gundelia tournefortii L. em parâmetros bioquímicos, atividades antioxidantes e danos ao DNA em um modelo de obesidade experimental de rato

The present study was designed to investigate the effects of Gundelia tournefortii L. plant extract on different tissues in terms of DNA damage, biochemical and antioxidant parameter values in rats with high-calorie diets. With this aim, Wistar albino male rats were divided into 4 groups containing 6 rats each and the study was completed over 12 weeks duration. At the end of the implementation process over the 12 weeks, rats were sacrificed and blood and tissue samples were obtained. Analyses were performed on blood and tissue samples. According to results for DNA damage (8-OHdG), in brain tissue the OG2 group was significantly reduced compared to the NC group. For MDA results in liver tissue, OG1 and OG2 groups were determined to increase by a significant degree compared to the control group, while the OG2 group was also increased significantly compared to the obese group. In terms of the other parameters, comparison between the groups linked to consumption of a high calorie diet (HCD) and administration of Gundelia tournefortii L. in terms of antioxidant activities and serum samples obtained statistically significant results. Gundelia tournefortii L. plant extracts had effects that may be counted as positive on antioxidant parameter activity and were especially identified to improve DNA damage and MDA levels in brain tissues. Additionally, consumption of Gundelia tournefortii L. plant extract in the diet may have antiobesity effects; thus, it should be evaluated for use as an effective weight-loss method and as a new therapeutic agent targeting obesity.

O presente estudo foi desenhado para investigar os efeitos do extrato da planta Gundelia tournefortii L. em diferentes tecidos em termos de danos ao DNA, valores de parâmetros bioquímicos e antioxidantes em ratos com dietas hipercalóricas. Com esse objetivo, ratos Wistar albinos machos foram divididos em 4 grupos contendo 6 ratos cada e o estudo foi concluído ao longo de 12 semanas de duração. No final desse processo de implementação, os ratos foram sacrificados e amostras de sangue e tecido foram obtidas. As análises foram realizadas em amostras de sangue e tecido. De acordo com os resultados para danos ao DNA (8-OHdG), no tecido cerebral o grupo OG2 foi significativamente reduzido em comparação com o grupo NC. Para os resultados de MDA no tecido hepático, os grupos OG1 e OG2 aumentaram significativamente em comparação ao grupo controle, enquanto o grupo OG2 também aumentou significativamente em comparação ao grupo obeso. Quanto aos demais parâmetros, a comparação entre os grupos ligados ao consumo de dieta hipercalórica (DC) e à administração de Gundelia tournefortii L. em termos de atividades antioxidantes e amostras de soro obteve resultados estatisticamente significativos. Os extratos de plantas de Gundelia tournefortii L. tiveram efeitos que podem ser considerados positivos na atividade dos parâmetros antioxidantes e foram especialmente identificados para melhorar os danos ao DNA e os níveis de MDA nos tecidos cerebrais. Além disso, o consumo de extrato vegetal de Gundelia tournefortii L. na dieta pode ter efeitos antiobesidade; portanto, deve ser avaliado para uso como um método eficaz de perda de peso e como um novo agente terapêutico voltado para a obesidade.

Effects of Gundelia tournefortii L. on biochemical parameters, antioxidant activities and DNA damage in a rat model of experimental obesity

Abstract The present study was designed to investigate the effects of Gundelia tournefortii L. plant extract on different tissues in terms of DNA damage, biochemical and antioxidant parameter values in rats with high-calorie diets. With this aim, Wistar albino male rats were divided into 4 groups containing 6 rats each and the study was completed over 12 weeks duration. At the end of the implementation process over the 12 weeks, rats were sacrificed and blood and tissue samples were obtained. Analyses were performed on blood and tissue samples. According to results for DNA damage (8-OHdG), in brain tissue the OG2 group was significantly reduced compared to the NC group. For MDA results in liver tissue, OG1 and OG2 groups were determined to increase by a significant degree compared to the control group, while the OG2 group was also increased significantly compared to the obese group. In terms of the other parameters, comparison between the groups linked to consumption of a high calorie diet (HCD) and administration of Gundelia tournefortii L. in terms of antioxidant activities and serum samples obtained statistically significant results. Gundelia tournefortii L. plant extracts had effects that may be counted as positive on antioxidant parameter activity and were especially identified to improve DNA damage and MDA levels in brain tissues. Additionally, consumption of Gundelia tournefortii L. plant extract in the diet may have antiobesity effects; thus, it should be evaluated for use as an effective weight-loss method and as a new therapeutic agent targeting obesity.

Resumo O presente estudo foi desenhado para investigar os efeitos do extrato da planta Gundelia tournefortii L. em diferentes tecidos em termos de danos ao DNA, valores de parâmetros bioquímicos e antioxidantes em ratos com dietas hipercalóricas. Com esse objetivo, ratos Wistar albinos machos foram divididos em 4 grupos contendo 6 ratos cada e o estudo foi concluído ao longo de 12 semanas de duração. No final desse processo de implementação, os ratos foram sacrificados e amostras de sangue e tecido foram obtidas. As análises foram realizadas em amostras de sangue e tecido. De acordo com os resultados para danos ao DNA (8-OHdG), no tecido cerebral o grupo OG2 foi significativamente reduzido em comparação com o grupo NC. Para os resultados de MDA no tecido hepático, os grupos OG1 e OG2 aumentaram significativamente em comparação ao grupo controle, enquanto o grupo OG2 também aumentou significativamente em comparação ao grupo obeso. Quanto aos demais parâmetros, a comparação entre os grupos ligados ao consumo de dieta hipercalórica (DC) e à administração de Gundelia tournefortii L. em termos de atividades antioxidantes e amostras de soro obteve resultados estatisticamente significativos. Os extratos de plantas de Gundelia tournefortii L. tiveram efeitos que podem ser considerados positivos na atividade dos parâmetros antioxidantes e foram especialmente identificados para melhorar os danos ao DNA e os níveis de MDA nos tecidos cerebrais. Além disso, o consumo de extrato vegetal de Gundelia tournefortii L. na dieta pode ter efeitos antiobesidade; portanto, deve ser avaliado para uso como um método eficaz de perda de peso e como um novo agente terapêutico voltado para a obesidade.

Effects of Gundelia tournefortii L. on biochemical parameters, antioxidant activities and DNA damage in a rat model of experimental obesity / Efeitos de Gundelia tournefortii L. em parâmetros bioquímicos, atividades antioxidantes e danos ao DNA em um modelo de obesidade experimental de rato

Abstract The present study was designed to investigate the effects of Gundelia tournefortii L. plant extract on different tissues in terms of DNA damage, biochemical and antioxidant parameter values in rats with high-calorie diets. With this aim, Wistar albino male rats were divided into 4 groups containing 6 rats each and the study was completed over 12 weeks duration. At the end of the implementation process over the 12 weeks, rats were sacrificed and blood and tissue samples were obtained. Analyses were performed on blood and tissue samples. According to results for DNA damage (8-OHdG), in brain tissue the OG2 group was significantly reduced compared to the NC group. For MDA results in liver tissue, OG1 and OG2 groups were determined to increase by a significant degree compared to the control group, while the OG2 group was also increased significantly compared to the obese group. In terms of the other parameters, comparison between the groups linked to consumption of a high calorie diet (HCD) and administration of Gundelia tournefortii L. in terms of antioxidant activities and serum samples obtained statistically significant results. Gundelia tournefortii L. plant extracts had effects that may be counted as positive on antioxidant parameter activity and were especially identified to improve DNA damage and MDA levels in brain tissues. Additionally, consumption of Gundelia tournefortii L. plant extract in the diet may have antiobesity effects; thus, it should be evaluated for use as an effective weight-loss method and as a new therapeutic agent targeting obesity.

Resumo O presente estudo foi desenhado para investigar os efeitos do extrato da planta Gundelia tournefortii L. em diferentes tecidos em termos de danos ao DNA, valores de parâmetros bioquímicos e antioxidantes em ratos com dietas hipercalóricas. Com esse objetivo, ratos Wistar albinos machos foram divididos em 4 grupos contendo 6 ratos cada e o estudo foi concluído ao longo de 12 semanas de duração. No final desse processo de implementação, os ratos foram sacrificados e amostras de sangue e tecido foram obtidas. As análises foram realizadas em amostras de sangue e tecido. De acordo com os resultados para danos ao DNA (8-OHdG), no tecido cerebral o grupo OG2 foi significativamente reduzido em comparação com o grupo NC. Para os resultados de MDA no tecido hepático, os grupos OG1 e OG2 aumentaram significativamente em comparação ao grupo controle, enquanto o grupo OG2 também aumentou significativamente em comparação ao grupo obeso. Quanto aos demais parâmetros, a comparação entre os grupos ligados ao consumo de dieta hipercalórica (DC) e à administração de Gundelia tournefortii L. em termos de atividades antioxidantes e amostras de soro obteve resultados estatisticamente significativos. Os extratos de plantas de Gundelia tournefortii L. tiveram efeitos que podem ser considerados positivos na atividade dos parâmetros antioxidantes e foram especialmente identificados para melhorar os danos ao DNA e os níveis de MDA nos tecidos cerebrais. Além disso, o consumo de extrato vegetal de Gundelia tournefortii L. na dieta pode ter efeitos antiobesidade; portanto, deve ser avaliado para uso como um método eficaz de perda de peso e como um novo agente terapêutico voltado para a obesidade.

The physiological and disturbing effects of surgical face masks in the COVID-19 era.

BACKGROUND: In the COVID-19 pandemic, the concern about mask-harmful effects disturbed mask-adherence. However, it is not certain whether the masks cause cardiopulmonary overload. OBJECTIVE: To investigate the physiological and disturbing effects of surgical face masks during exercise. METHOD: The study was conducted in a tertiary hospital with 100 healthy volunteers between September 2020 and January 2021. Individuals with impaired walking, cardiopulmonary disease, and smoking were not included in the study. Initially, respiratory rate (RR), heart rate (HR), oxygen saturation (SpO2), end-tidal carbon dioxide (EtCO2) were measured.  Participants underwent 6-minute walking test (6MWT) with and without surgical masks.  Mask-discomfort questionnaire was applied before and after 6 MWT with the mask. RESULTS: Surgical masks during 6 MWTs significantly increased HR, RR, and EtCO2 levels (p<0.001).  Walking distance (p<0.001) and SpO2 level (p=0.002) were significantly decreased with mask. In Mask-Discomfort Questionnaire, humidity, temperature, resistance, salinity, odor, fatigue (p<0.001), and itching (p=0.001) scores significantly increased after 6MWT with mask. CONCLUSION: In healthy volunteers, HR, RR, EtCO2 were increased, and SpO2 and walking distance were decreased in the short-term, light exercise performed with the surgical mask. Findings support the concern that masks may cause cardiopulmonary overload (Tab. 3, Fig. 1, Ref. 17). Text in PDF www.elis.sk Keywords: COVID-19, masks, physiology, psychological side effects, questionnaire.

Effects of Gundelia tournefortii L. on biochemical parameters, antioxidant activities and DNA damage in a rat model of experimental obesity.

The present study was designed to investigate the effects of Gundelia tournefortii L. plant extract on different tissues in terms of DNA damage, biochemical and antioxidant parameter values in rats with high-calorie diets. With this aim, Wistar albino male rats were divided into 4 groups containing 6 rats each and the study was completed over 12 weeks duration. At the end of the implementation process over the 12 weeks, rats were sacrificed and blood and tissue samples were obtained. Analyses were performed on blood and tissue samples. According to results for DNA damage (8-OHdG), in brain tissue the OG2 group was significantly reduced compared to the NC group. For MDA results in liver tissue, OG1 and OG2 groups were determined to increase by a significant degree compared to the control group, while the OG2 group was also increased significantly compared to the obese group. In terms of the other parameters, comparison between the groups linked to consumption of a high calorie diet (HCD) and administration of Gundelia tournefortii L. in terms of antioxidant activities and serum samples obtained statistically significant results. Gundelia tournefortii L. plant extracts had effects that may be counted as positive on antioxidant parameter activity and were especially identified to improve DNA damage and MDA levels in brain tissues. Additionally, consumption of Gundelia tournefortii L. plant extract in the diet may have antiobesity effects; thus, it should be evaluated for use as an effective weight-loss method and as a new therapeutic agent targeting obesity.

Evening preference correlates with regional brain volumes in the anterior occipital lobe.

Chronotype or diurnal preference is a questionnaire-based measure influenced both by circadian period and by the sleep homeostat. In order to further characterize the biological determinants of these measures, we used a hypothesis-free approach to investigate the association between the score of the morningness-eveningness questionnaire (MEQ) and the Munich chronotype questionnaire (MCTQ), as continuous variables, and volumetric measures of brain regions acquired by magnetic resonance imaging (MRI). Data were collected from the Baependi Heart Study cohort, based in a rural town in South-Eastern Brazil. MEQ and anatomical 1.5-T MRI scan data were available from 410 individuals, and MCTQ scores were available from a subset of 198 of them. The average MEQ (62.2 ± 10.6) and MCTQ (average MSFsc 201 ± 85 min) scores were suggestive of a previously reported strong general tendency toward morningness in this community. Setting the significance threshold at P > .002 to account for multiple comparisons, we observed a significant association between lower MEQ score (eveningness) and greater volume of the left anterior occipital sulcus (ß = -0.163, p = .001) of the occipital lobe. No significant associations were observed for MCTQ. This may reflect the smaller dataset for MCTQ, and/or the fact that MEQ, which asks questions about preferred timings, is more trait-like than the MCTQ, which asks questions about actual timings. The association between MEQ and a brain region dedicated to visual information processing is suggestive of the increasingly recognized fluidity in the interaction between visual and nonvisual photoreception and the circadian system, and the possibility that chronotype includes an element of masking.

Metabolic syndrome alters relationships between cardiometabolic variables, cognition and white matter hyperintensity load.

Cardiometabolic risk factors influence white matter hyperintensity (WMH) development: in metabolic syndrome (MetS), higher WMH load is often reported but the relationships between specific cardiometabolic variables, WMH load and cognitive performance are uncertain. We investigated these in a Brazilian sample (aged 50-85) with (N = 61) and without (N = 103) MetS. Stepwise regression models identified effects of cardiometabolic and demographic variables on WMH load (from FLAIR MRI) and verbal recall performance. WMH volume was greater in MetS, but verbal recall performance was not impaired. Age showed the strongest relationship with WMH load. Across all participants, systolic blood pressure (SBP) and fasting blood glucose were also contributors, and WMH volume was negatively associated with verbal recall performance. In non-MetS, higher HbA1c, SBP, and number of MetS components were linked to poorer recall performance while higher triglyceride levels appeared to be protective. In MetS only, these relationships were absent but education exerted a strongly protective effect on recall performance. Thus, results support MetS as a construct: the clustering of cardiometabolic variables in MetS alters their individual relationships with cognition; instead, MetS is characterised by a greater reliance on cognitive reserve mechanisms. In non-MetS, strategies to control HbA1c and SBP should be prioritised as these have the largest impact on cognition.

Role of endothelin receptors and relationship with nitric oxide synthase in impaired erectile response in diabetic rats.

To evaluate the protective role of bosentan (BOS), an endothelin-1 (ET-1) receptor antagonist, and to show the changes in rats with experimentally induced diabetic erectile dysfunction (ED), a total of 24 albino Wistar rats were allocated into four groups. Group 1 was the healthy group and Group 2 had diabetes mellitus (DM) induced by intraperitoneal injection of 60 mg kg-1 streptozotocin (STZ). Following the establishment of DM, Group 3 and Group 4 were treated with oral BOS doses of 50 mg kg-1 and 100 mg kg-1 , respectively, for 60 days. At the end of the treatment, we evaluated yawning and erection response to apomorphine treatment and then the animals were sacrificed. ET-1, eNOS, iNOS, tumour necrosis factor (TNF)-α, ET-RA and ET-RB mRNA expressions were analysed in cavernosal tissue. It was observed that yawning and erection response decreased in the diabetic group; however, both of these improved with BOS treatment. While ET-1, TNF-α and iNOS gene expressions increased, eNOS, ET-RA and ET-RB gene expressions decreased in the DM group compared to the healthy group. DM has a negative impact on cavernosal tissue blood flow through activating vasoconstrictor mediators in cavernosal tissue. BOS regulates significantly eNOS, iNOS and TNF-α expressions in a dose-dependent manner.

Differences in nephrotoxicity risk and renal effects among anti-viral therapies against hepatitis B.

BACKGROUND: Results are conflicting with respect to the renal effects of anti-viral agents used for hepatitis B virus infection. AIM: To compare short and long-term renal effects in real-life settings and to determine risk factors for renal impairment during treatment. METHODS: 2221 treatment-naïve patients were enrolled. Among these, 895 (302 lamivudine, 27 telbivudine, 282 entecavir, 273 tenofovir and 11 adefovir initiated patients) had 'repeated measures' of creatinine (baseline, 1st, 6th, 12th and 24th month of treatment). Telbivudine and adefovir groups were excluded from further analysis because of the low number of patients. We calculated the glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) formula at each time point. Hypophosphataemia was also recorded. Risk factors for renal impairment were analysed. RESULTS: Tenofovir caused a decline in GFR at each time point when compared to baseline levels. However, lamivudine and entecavir did not change GFR. GFR-shifting from ≥90 to 60-89 mL/min/1.73 m(2) was comparable among groups. The proportion of patients whose baseline creatinine increased more than 25% was comparable among all anti-virals. GFR showed a decline in patients who switched from entecavir to tenofovir. One patient with compensated cirrhosis needed to change from tenofovir because of renal safety. Seven and three patients developed transient hypophosphataemia in the tenofovir and lamivudine groups, respectively. CONCLUSIONS: Although tenofovir caused a decline in GFR, differences between the anti-viral agents do not appear to be so impressive. In patients with and without renal risk factors at baseline, there is no impact of anti-virals, including tenofovir.

Histological comparison of healing following tooth extraction with ridge preservation using enamel matrix derivatives versus Bio-Oss Collagen: a pilot study.

The goal of the present clinical study was to evaluate new bone formation in human extraction sockets augmented with enamel matrix derivatives (EMD) and Bio-Oss Collagen. Patients with symmetrical single-rooted teeth in the bilateral quadrants of the upper jaw condemned for extraction participated in this study. Following extraction, the sockets (20 sockets) were randomly augmented using either EMD or Bio-Oss Collagen. After 3 months of healing, bone biopsies were obtained and prepared for histological analyses. Dental implants were then placed. Implant stability quotient (ISQ) readings were obtained for each implant at the time of surgery and at 1 and 3 months postoperatively. The mean new bone formation was 34.57 ± 25.67% in the EMD sites and 28.80 ± 16.14% in the Bio-Oss Collagen sites. There was no significant difference between the groups. The ISQ values were significantly higher for the implants placed in the EMD sites at the first and third months, but no significant differences were observed in the ISQ values for the implants placed in the Bio-Oss Collagen sites. The augmentation of the extraction sockets with EMD or Bio-Oss Collagen leads to similar behaviour in bone regeneration.

EMD or subepithelial connective tissue graft for the treatment of single gingival recessions: a pilot study.

BACKGROUND AND OBJECTIVE: The combination of EMD with root-coverage procedures has been shown to promote periodontal regeneration on the exposed root surface. The aim of this randomized clinical study was to compare the efficacy of EMD with connective tissue graft (CTG) for the treatment of Miller Class I and Class II single recessions in a split-mouth design. MATERIAL AND METHODS: The study included 12 systemically healthy patients, each with two single bilateral gingival recession defects (24 recessions). One recession defect in each patient was treated with the coronally advanced flap (CAF) + EMD procedure and the other recession defect was treated with the CTG + EMD procedure, in a split-mouth study design. The parameters recession depth (RD), recession width, percentage of root coverage, height of keratinized tissue (HKT), gingival thickness, probing depth and clinical attachment level (CAL) were recorded at baseline. All parameters, except for gingival thickness, were remeasured at 6 and 12 mo. RESULTS: The mean percentage root coverage at the final evaluation was 92 ± 14% for the CAF + EMD group and 89 ± 14% for the CAF + CTG group. Both treatments resulted in statistically significant (p < 0.05) decreases in RD and recession width, and increases in HKT, at 6 and 12 mo. There was also a significant decrease in the probing depth and a significant gain in the CAL for both groups. The probing depth was statistically higher in the CAF + CTG group than in the CAF + EMD group at 6 mo (p < 0.05), while the CAL was statistically lower in the CAF + EMD group than in the CAF + CTG group at 6 and 12 mo (p < 0.05). CONCLUSION: The present study demonstrated that both CAF + EMD and CAF + CTG procedures were similarly successful in treating Miller Class I and Class II single gingival recession defects.

Reproducibility of technetium-99m ethylenedicysteine clearance.

It has been shown that technetium-99m ethylenedicysteine ((99m)Tc-EC) clearance displays a strong correlation with orthoiodohippurate clearance and that it is possible to estimate effective renal plasma flow from (99m)Tc-EC clearance. However, in routine practice, when monitoring renal function of patients by clearance determinations it is imperative to test the reproducibility of the clearance technique in order to decide whether the changes in renal function are related to disease or not. The aim of this study was to test the reproducibility of (99m)Tc-EC clearance. The study group comprised 13 patients aged between 24 and 58 years (eight female and five male). Two patients had single kidneys due to agenesis and hypoplasia. Plasma creatinine and BUN levels were within the normal range and remained stable between two clearance studies. None of the patients were receiving medication. Two separate multiple sample clearance studies were performed in each patient within a week. The difference between two studies was expressed as a percentage of the mean value of the two studies, and the standard deviation of these percentages represented the precision. The plasma clearance of (99m)Tc-EC in the first-step studies ranged from 190 ml/min to 561 ml/min with a mean of 411+/-101 ml/min. The clearances obtained from the second-step studies ranged from 248 ml/min to 552 ml/min, with a mean of 387+/-94 ml/min. There was no statistically significant difference between the two clearance studies (P>0.05). There was a mean difference of 5.3% between the first and second clearance studies, and the precision was found to be 12.7%. In conclusion, this study suggested that consecutive (99m)Tc-EC clearance measurements should be interpreted cautiously.

Prospective validation of single plasma sample 99mTc-ethylenedicysteine clearance in adults.

UNLABELLED: 99mTc-L,L-ethylene, L, dicysteine (EC) clearance shows strong correlation with orthoiodohippurate clearance, and it is possible to estimate effective renal plasma flow from 99mTc-EC clearance. In routine clinical studies, it is practical to use the one or two plasma sample method instead of multiple plasma samples for clearance determination. A single-sample technique was developed for 99mTc-EC, and a regression formula was generated. A prospective study tested the validity of this regression formula. METHODS: The study population was composed of 26 patients with a wide range of renal function. Multiple plasma sample 99mTc-EC clearances were calculated from all patients using the open two-compartment model. Single plasma sample clearances were also determined from the 54-min plasma sample using the regression formula published previously. RESULTS: The multiple-sample plasma clearance of 99mTc-EC ranged from 46 to 668 mL/min with a mean of 300.76 +/- 150.73 mL/min. The clearances obtained from the 54-min plasma sample ranged from 49 to 699 mL/min, with a mean of 297.39 +/- 152.23 mL/min. There was an excellent correlation between the clearances obtained by the two techniques (r = 0.99, slope = 0.9911). The standard error of estimation was found to be 25.9 mL/min. CONCLUSION: This study suggests that 99mTc-EC clearance can be estimated from 54-min plasma samples with an acceptable error of estimation for most routine clinical studies.

Simplified technetium-99m-EC clearance in adults from a single plasma sample.

UNLABELLED: Technetium-99m-EC has recently been introduced as an alternative renal tubular agent to 131I-ortho iodohippurate (OIH). It has been shown that 99mTc-EC clearance shows strong correlation with OIH clearance and it is possible to estimate effective renal plasma flow. In routine clinical studies, it is practical to use one or two plasma sample methods instead of multiple plasma samples for clearance determination. An attempt was made to determine 99mTc-EC clearance with one sample method. METHODS: Data from 72 subjects were collected. To increase the range of renal function, two anuric hemodialysis patients were also included. Clearances were determined by the open two-compartment model. RESULTS: The clearance range was 12 ml/min to 660 ml/min with a mean of 275 +/- 117 ml/min. Analysis of correlation was made by Tauxe's method. The least standard error of estimation (s.e.e. = 32.71 ml/min) and the best correlation (r = 0.97) between the theoretical volume distribution and the clearance estimations were obtained from the 54-min plasma sample. CONCLUSION: This study suggests that EC clearance could be determined by a simplified single-sample method with an acceptable s.e.e.