Deviations from Beers were used to study the equilibrium between monomer and dimer froms of the water soluble TPPS2 , TPPS3 andTPPS4 porphyrins at various ionic strength valuse.At on ionic strength of 0.1 M PH=7 the dimerization order was Trans- TPPS 2 > CiSTPPS 2» TPPS3 > TPPS4. The symmetry of the porphyrins with the same charges are found to influence the magnitude of the dimerization constant KD . The KD values increased with an increase in ionic strength, and when extrapolated to 1=0, the compounds were still predictes to be associated. Intermolecular II-II interactions were used to explain the dimerization phenomena obserbved. DMSO/H20 was used as solvent to monomerize all of the metal free porphyrins.

Background: Considering the and importance of formation of atrial Thrombus (AT) in patients who had developed atrial fibrilation (AF) and its early diagnosis, and with some regards to several reports on benefits of applying the D-Dimer test in such conditions, this study was carried out to detemine the accuracy and value of this test compared to the gold standard method of Trans-Esophageal Echocardiography (TEE) in patients referring to Modarres hospital. Materials and Methods: This clinical trial was performed on 73 patients whom were diagnosed as having AF. A more accurate method of TEE was applied to confirm if they had atrial thrombi. For determination of value of D-Dimer test in diagnosis of AT, 5ccof blood was taken from any subjects. The results were regarded normal if the D-Dimer level was less than 500 ng/ml. Then positive and negative predictive values (PPV & NPV) were calculated as diagnostic measurements. Results: Of the 73 subjects of this study (67% women versus 33% men) with mean age of 44.7±12 years old, there was 53.4% who had the history of Warfarin usage. According to the results of D-Dimer test, 33% had reached to positive levels, whereas 67% revealed to have no thrombus. The PPV of this test was calculated 48.6% and the NPV was 81.6%. Conclusion: Regarding the present condition of our patients and the excessive use of Warfarin among them and also probable failures of D-Dimer test, this test does not have the acceptible capability (particularly duringin these situations) in diagnosing AT.

Background & aim: D-dimer levels have been recognized as significant markers for assessing disease severity and mortality in patients with COVID-19. This research aims to examine the correlation between D-dimer levels and disease severity in hospitalized COVID-19 patients. Methods: Conducted over an eight-month period from March 2023 to January 2024, this cross-sectional study evaluated 231 confirmed COVID-19 patients admitted to Chamran Hospital. D-dimer levels, along with clinical and Para clinical data, were collected and analyzed. Disease severity was assessed through pulse oximetry and measurements of blood oxygen saturation (SpO2). Results: The present study was carried out on 134 males (58%) and 97 females (42%), with a mean age of 61 years. Elevated D-dimer levels were correlated with decreased SpO2 levels. Patients with SpO2 below 90% exhibited significantly higher mean D-dimer levels compared to those with SpO2 above 90% (2589 vs. 517 Nano grams per milliliter, P>0. 001). Additionally, a moderate negative correlation was found between D-dimer levels and SpO2 (r=-0. 624). Conclusion: The inverse correlation between D-dimer levels and SpO2, indicative of disease severity in COVID-19 patients, suggests that D-dimer levels can serve as a predictive biomarker in these patients.

Background: Recently, D- dimer has been designated as a biomarker with potential for diagnosis & management of pre- eclampsia.Objective: To determine the correlation between pre-eclampsia and D- dimer and also comparing of results with those of control group obtained at third trimester.Methods: This was a descriptive analytical study performed on pregnant women at their third trimester. The patients were divided into two groups of 30 members marked as case group with pre- eclampsia and control group with normal pregnancy. Plasma level of D- dimer was quantitatively measured by agglutination technique.Findings: Pre-eclampsia showed a significant correlation with plasma D- dimer. In third trimester, pre-eclamptic women were demonstrated to have significantly higher levels of D- dimer compared with normal pregnant women, 721.43±401.13 vs. 322.26±117.65 ng/ml (P<0.001). D-dimer was also shown to have a positive correlation with severity of condition in pre- eclamptic women.Conclusion: Regarding the data obtained in present study, plasma D-dimer level may be a potential biomarker for hematologic and fibrinolytic changes occurs in pre-eclampsia. Also, D- dimer could be considered as a biomarker to evaluate the risk factors of pre-eclampsia.

Background: The diagnosis of acute febrile urinary tract infection (UTI) relies on various clinical and laboratory findings, which have shown conflicting results.Objectives: This study aimed to evaluate the utility of serum D-dimer in distinguishing acute pyelonephritis (APN) from other acute bacterial febrile infections.Methods: This cross-sectional study included 47 children with a confirmed UTI (verified by positive urine culture) and 47 children with other bacterial febrile infections. Serum D-dimer levels were measured in all patients before starting antibacterial treatment.Results: A total of 94 febrile children were evaluated, with females outnumbering males. Significant differences between the two groups were observed for microscopic hematuria (P = 0.044), bacteriuria (P < 0.001), white blood cell (WBC) count (P = 0.047), and hemoglobin (Hgb) (P = 0.035), but not for serum D-dimer (P = 0.327). Binary logistic regression analysis revealed that Hgb (P = 0.019) had a significant predictive value in APN, whereas serum D-dimer did not. Serum D-dimer was found to be an inaccurate biomarker for distinguishing febrile UTI from other bacterial febrile infections.Conclusions: Based on our findings, while D-dimer level increase in various acute bacterial febrile infections, they are not appropriate in differentiating febrile UTI from other bacterial infections.