Combining in vivo pathohistological and redox status analysis with in silico toxicogenomic study to explore the phthalates and bisphenol A mixture-induced testicular toxicity

The aim of this study was to: (i) determine and compare the capacity of bis (2 -ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), bisphenol A (BPA), and their mixture to produce testicular toxicity after the subacute exposure; (ii) explore the mechanisms behind the observed changes using in silico toxicogenomic approach. Male rats were randomly split into groups (n = 6): (1) Control (corn oil); (2) DEHP (50 mg/kg b.w./day); (3) DBP (50 mg/kg b.w./day); (4) BPA (25 mg/kg b.w./day); and (5) MIX (50 mg/kg b.w./day DEHP + 50 mg/kg b.w/day DBP + 25 mg/kg b.w./day BPA). Animals were sacrificed after 28 days of oral exposure, testes were extracted and prepared for histological assessments under the light microscope (haematoxylin and eosin staining) and redox status analysis. The Comparative Toxicogenomics Database (CTD; http://CTD.mdibl.org), Cytoscape software (https://cytoscape.org) and ToppGene Suite (https://toppgene.cchmc.org) were used for data-mining. Present pathohistological study has demonstrated more pronounced testicular toxicity of the MIX group (desquamated germinal epithelium cells, enlarged cells with hyperchromatic nuclei, multinucleated cell forms and intracytoplasmic vacuoles) in comparison with the single substances, while effects on redox status parameters were either more prominent, or present only in the MIX group. In silico investigation revealed 20 genes linked to male reproductive disorders, affected by all three investigated substances. Effects on metabolism, AhR pathway, apoptosis and oxidative stress could be singled out as the most probable mechanisms involved in the subacute DEHP, DBP and BPA mixture testicular toxicity, while the effect on oxidative stress parameters was confirmed by in vivo experiment.

Lipid profile and lipid oxidative modification parameters in the first trimester of high- risk pregnancies - possibilities for preeclampsia prediction

OBJECTIVES

The goal of this study was to investigate metabolic changes in lipids and oxidative stress parameters in the first trimester of pregnancy with the more specific aim of estimating the significance and strength of researched parameters in the prediction of preeclampsia.

DESIGN AND METHODS

The study included 87 high-risk pregnant (HRG) female subjects, 14 with developed preeclampsia (PEC) and 43 healthy pregnant female subjects matched for gestational age (CG). Thiobarbituric acid-reactive substances (TBARS) concentration, lipid hydroperoxides (LOOH), pro-oxidant antioxidant balance (PAB) and total oxidative status (TOS) were measured as oxidative stress markers, while total antioxidant capacity (TAC) was measured as an antioxidative defense parameter. The Atherogenic Index of Plasma (AIP) was calculated as the base 10 logarithm of the ratio of the plasma concentration of triglycerides (TG) to the plasma concentration of high-density lipoprotein cholesterol (HDL-C), with each concentration expressed in mmol/L.

RESULTS

The results have shown that lipid indices, especially AIP, were significantly higher in the first trimester of HRG (p < 0.001) and PEC (p < 0.001). Oxidative stress parameters were significantlly higher, while TAC was significantly lower in HRG vs. CG [0.7 ± 0.15 vs 1.1 ± 0.16; (p < 0.001)] and in PEC [0.6 ± 0.12 vs 1.1 ± 0.16; (p < 0.001)] vs. CG. Also, in the HRG, results have shown an independent association of AIP with the preeclampsia development (p < 0.05), while placental growth factor did not show the expected level of significance (p = 0.648). Analysis of the Receiver Operating Characteristics (ROC) curves indicated that certain parameters included in the research model have very good diagnostic accuracy for preeclampsia (AUC = 0.856).

CONCLUSIONS

AIP is associated with high-risk pregnancies. Furthermore, our results firmly underscored AIP as a potential marker for preeclampsia prediction.

Oxidative Stress and Inflammatory Markers PTX3, CypA, and HB-EGF: How Are They Linked in Patients With STEMI?

We investigated circulating levels of inflammatory biomarkers pentraxin-3 (PTX3), cyclophilin A (CypA), and heparin-binding epidermal growth factor-like growth factor (HB-EGF); oxidative stress; and antioxidant status markers in the patients with ST-segment elevation acute myocardial infarction (STEMI) to better understand a relationship between inflammation and oxidative stress. We examined the impact of oxidative stress on high values of inflammatory parameters. The study included 87 patients with STEMI and 193 controls. We observed a positive correlation between PTX3 and HB-EGF (ρ = 0.24, P = .027), CyPA, and sulfhydryl (SH) groups (ρ = 0.25, P = .026), and a negative correlation between PTX3 and SH groups (ρ = -0.35, P = .001) in patients with STEMI. To better understand the effect of the examined parameters on the occurrence of high concentrations of inflammatory parameters, we grouped them using principal component analysis. This analysis identified the 4 most contributing factors. Optimal cutoff values for discrimination of patients with STEMI from controls were calculated for PTX3 and HB-EGF. An independent predictor for PTX3 above the cutoff value was a "metabolic-oxidative stress factor" comprised of glucose and oxidative stress marker prooxidant-antioxidant balance (odds ratio = 4.449, P = .030). The results show that higher PTX3 values will occur in patients having STEMI with greater metabolic and oxidative stress status values.

Paraoxonase 1 and atherosclerosis-related diseases

A direct and an indirect relationship between paraoxonase 1 (PON1) and atherosclerosis exists. Given PON1's physical location within high-density lipoprotein (HDL) particles and its recognized enzyme activity, it is certainly reasonable to suggest that PON1 facilitates the antiatherogenic nature of HDL particles. PON1 also plays a role in regulating reverse cholesterol transport, antioxidative, anti-inflammatory, antiapoptotic, vasodilative, and antithrombotic activities and several endothelial cell functions. HDL dysfunctionality is a more recent issue and seems to be centered on pathological conditions affecting HDL structure and size profiles. This review is focused on the role of PON1 status in different atherosclerosis-related diseases that we have studied over the last twenty years (coronary heart disease, acute ischemic stroke, diabetes mellitus type 2, end-stage renal disease, chronic obstructive pulmonary disease, and sarcoidosis) with the aim to determine the true value of PON1 as a biomarker. The role of PON1 in cancer is also covered, as risk factors and mechanisms underlying both atherosclerosis and cancer share common features.

Effect of propolis and N-acetylcysteine supplementation on lipoprotein subclasses distribution and paraoxonase 1 activity in subjects with acute respiratory infection

Background

Propolis and N-acetylcysteine have positive impact on respiratory tract health. Also, it has been suggested that they have beneficial effects on serum lipid and oxidative stress status, but the available data are limited and mostly gained from animal models. In this study we evaluated the effects of propolis and N-acetylcysteine supplementation (PropoMucil®) on lipid status, lipoprotein subclasses distribution and paraoxonase 1 activity in subjects with acute respiratory infection.

Methods

Twenty subjects with acute respiratory infection were included. PropoMucil® granules for oral solution (80 mg of dry propolis extract and 200 mg of N-acetylcysteine) were administered tree times per day for ten days. Serum lipid profile, paraoxonase 1 activity and low-density and high-density lipoprotein size and subclasses distribution were assessed at baseline and after supplementation.

Results

Following ten days of supplementation lipid status remained unchanged, but a significant increase of low-density lipoprotein particle size and proportion of high-density lipoprotein 3a particles were found (P<0.05). Moreover, supplementation with PropoMucil® significantly improved high-density lipoprotein particles distribution, particularly in those who smoke. There was a moderate increase of paraoxonase 1 activity, but without statistical significance.

Conclusions

The presented study demonstrated that short-term supplementation with PropoMucil® has beneficial effects on low-density and high-density lipoprotein subclasses distribution and paraoxonase 1 activity in subjects with acute respiratory infection particularly in those who smoke.

Serum Resistin, Adenylate Cyclase-Associated Protein 1 Gene Expression, and Carotid Intima-Media Thickness in Patients with End-Stage Renal Disease and Healthy Controls

BACKGROUND

Human resistin is a proinflammatory cytokine with significant proatherogenic effects which acts through adenylyl cyclase-associated protein 1 (CAP1). Chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients have increased cardiovascular risk and resistin levels. Previous studies indicated resistin significance as a predictor of mortality in CKD.

AIMS

We sought to investigate plasma resistin levels, peripheral blood mononuclear cell (PBMC) resistin mRNA, and for the first time CAP1 mRNA levels in ESRD patients and healthy controls. We also sought to investigate the relation of resistin and CAP1 to carotid intima media thickness (CIMT), CD36 gene expression, and matrix metalloproteinase 9 (MMP-9) circulating levels in ESRD patients and healthy controls.

METHODS

This study included 33 patients with ESRD and 27 healthy controls. Resistin and MMP-9 levels were measured by ELISA. Resistin, CAP1, and CD36 PBMC mRNA were measured by quantitative PCR.

RESULTS

Our study showed that ESRD patients have significantly higher levels of circulatory resistin compared to healthy controls (p < 0.001), while there was no significant difference in resistin mRNA. A significant upregulation of CAP1 and CD36 was observed in the ESRD group (p < 0.001; p < 0.001). Resistin concentration correlated with CIMT in healthy controls (r = 0.512, p = 0.036), and with MMP-9 concentration in ESRD (r = 0.353, p = 0.044) and healthy controls (r = 0.463, p = 0.026). CAP1 correlated positively with CIMT (r = 0.464, p = 0.008) in ESRD, and with CD36 in healthy controls (r = 0.447, p = 0.022) and ESRD (r = 0.824, p < 0.001).

CONCLUSION

The obtained data suggest that high levels of circulating resistin acting upon cells with an upregulated CAP1 gene could contribute to the increased inflammation and accelerated atherosclerosis seen in CKD patients.

Prostate Cancer Probability Prediction By Machine Learning Technique

The main goal of the study was to explore possibility of prostate cancer prediction by machine learning techniques. In order to improve the survival probability of the prostate cancer patients it is essential to make suitable prediction models of the prostate cancer. If one make relevant prediction of the prostate cancer it is easy to create suitable treatment based on the prediction results. Machine learning techniques are the most common techniques for the creation of the predictive models. Therefore in this study several machine techniques were applied and compared. The obtained results were analyzed and discussed. It was concluded that the machine learning techniques could be used for the relevant prediction of prostate cancer.

Prooxidant-antioxidant balance, advanced oxidation protein products and lipid peroxidation in Serbian patients with Parkinson's disease

BACKGROUND

Biomarkers of oxidative stress are relevant in the evaluation of the disease status and prooxidant-antioxidant balance, advanced oxidation protein products and lipid peroxidation products (malondialdehyde and 4-hydroxynonenal) are being extensively evaluated regarding their relationship with clinical presentation and disease severity.

AIM OF THE STUDY

The aim of this study was to evaluate the levels of the above-mentioned parameters in plasma of 39 men and 17 women with Parkinson's disease, originated from the Republic of Serbia and their relation to clinicopathological characteristics (gender, age at examination, duration of the disease, and Hoehn and Yahr score) and oxidative status.

RESULTS

The incidence of disease was 2:1 towards males. The investigated oxidative parameters were gender and Hoehn and Yahr related. Significant association of higher Hoehn and Yahr scores was observed for malondialdehyde (p = 0.01) and prooxidant-antioxidant balance (p = 0.02). Relation between oxidant-antioxidant status was further supported by observed positive correlation between 4-hydroxynonenal (p = 0.04) and prooxidant-antioxidant balance (p = 0.03). Finally, the multivariate analysis indicated that prooxidant-antioxidant balance and malondialdehyde were partially determined by gender (10.6% and 7.6%) and Hoehn and Yahr scores (13.6% and 18.8%), while Hoehn and Yahr scores contributed to the variance of advanced oxidation protein products with 13.2%.

CONCLUSION

Our results indicate the higher level of oxidative stress (oxidant-antioxidant imbalance) and possible relation of several markers with gender and disease stage in patients with Parkinson's disease. The analyzed markers could be used to specify the severity of oxidative stress; however, their potential value should be analyzed in further studies.

Association of Pentraxin-3, Galectin-3 and Matrix Metalloproteinase-9/Timp-1 with Cardiovascular Risk in Renal Disease Patients

Inflammation, apoptosis and extracellular remodeling play significant roles in cardiovascular disease (CVD) underlying the major causes of mortality in renal patients. In 19 pre-dialysis patients, 21 dialysis patients and 20 control subjects, the concentrations of pentraxin-3, galectin-3, MMP-9 and TIMP-1 were determined by ELISA. CVD risk was calculated according to the Framingham risk score algorithm. Pentraxin-3 was increased in renal patients compared to healthy controls (p<0.001). In contrast, galectin-3 was reduced in hemodialysis patients compared to pre-dialysis patients and controls (p<0.001). In addition, MMP-9 and TIMP-1 were elevated in renal patients compared to controls (p<0.01 and p<0.001, respectively). Logistic regression analyses disclosed associations of galectin-3, MMP-9, pentraxin-3 and glomerular filtration with calculated CVD risk score. Combined testing of pentraxin-3, galectin-3, MMP-9 and glomerular filtration rate can discriminate renal patients with high and low risk of a coronary event.

Alterations of HDL Particles in Children with End-stage Renal Disease

Background

Unfavorable lipid profile presents one of most important risk factor for cardiovascular disease in renal pathology. Myeloperoxidase (MPO) as enzyme which oxidizes lipoproteins and paraoxonase1 (PON1) as anti-oxidative enzyme have been involved in pathogenesis of cardiovascular disease. In the present study we sought to assess oxidative stress status, lipoprotein subclasses distribution as well as functionality of high density lipoprotein (HDL) trough MPO/PON1 ratio in children with chronic kidney disease (CKD) and children after renal transplantation.

Methods

PON1 activity and oxidative stress parameters were measured spectrophotometrically, while MPO concentration was determined using immunoassay. Separation of lipoprotein subclasses was performed by vertical gradient gel electrophoresis in 19 children with different stage of CKD and 19 post-transplantation patients (PT).

Results

CKD patients had increased MPO/PON1 ratio and higher prevalence of smaller HDL subclasses when compared to PT subjects. Also, there was a significant positive correlation between MPO level and MPO/PON1 ratio with relative proportion of smaller HDL subclasses.

Conclusion

Children with CKD have impaired HDL distribution that is improved after kidney transplantation. Since that measurement of HDL distribution and functionality are not routinely available, MPO/PON1 ratio may be useful marker that could provide necessary information.

Association of Myeloperoxidase and the Atherogenic Index of Plasma in Children with End-Stage Renal Disease

BACKGROUND

The aim of this study was to explore oxidative stress status, especially the enzyme myeloperoxidase in children with end-stage renal disease. Also, we investigated possible associations between the atherogenic index of plasma and these parameters.

METHODS

Lipid status parameters, oxidative stress status parameters, and myeloperoxidase concentration were measured in the sera of 20 children in the last stage of chronic renal disease (ESRD) and 35 healthy children of matching age and sex. The Atherogenic Index of Plasma (AIP) was calculated according to the appropriate equation.

RESULTS

We did not find any significant differences in myeloperoxidase concentrations between the investigated groups (p=0.394). Oxidative stress parameters were, however, significantly higher in the patient group (p<0.001), as well as the atherogenic index of plasma (p<0.001). Myeloperoxidase concentration and advanced oxidation protein product (AOPP) concentration were independently associated with increased AIP in the patient group (p<0.05).

CONCLUSIONS

Changes in AIP in children with ERSD are associated with the oxidative stress status and myeloper-oxidase concentration.

Gut-associated lymphoid tissue, gut microbes and susceptibility to experimental autoimmune encephalomyelitis

Gut microbiota and gut-associated lymphoid tissue have been increasingly appreciated as important players in pathogenesis of various autoimmune diseases, including multiple sclerosis. Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis that can be induced with an injection of spinal cord homogenate emulsified in complete Freund's adjuvant in Dark Agouti (DA) rats, but not in Albino Oxford (AO) rats. In this study, mesenteric lymph nodes (MLN), Peyer's patches (PP) and gut microbiota were analysed in these two rat strains. There was higher proportion of CD4(+) T cells and regulatory T cells in non-immunised DA rats in comparison to AO rats. Also, DA rat MLN and PP cells were higher producers of pro-inflammatory cytokines interferon-γ and interleukin-17. Finally, microbial analyses showed that uncultivated species of Turicibacter and Atopostipes genus were exclusively present in AO rats, in faeces and intestinal tissue, respectively. Thus, it is clear that in comparison of an EAE-susceptible with an EAE-resistant strain of rats, various discrepancies at the level of gut associated lymphoid tissue, as well as at the level of gut microbiota can be observed. Future studies should determine if the differences have functional significance for EAE pathogenesis.

Effect of alpha-lipoic acid supplementation on oxidative stress markers and antioxidative defense in patients with schizophrenia

BACKGROUND

The purpose of this study was to examine the effects of alpha-lipoic acid (LA) supplementation on oxidative stress markers in patients with schizophrenia.

SUBJECTS AND METHODS

Eighteen (18) medicated patients with schizophrenia and 38 healthy controls received daily supplements of LA (500 mg/day) for three months. At baseline, 45th and 90th days of supplementation, venous blood collected for analysis of oxidative stress markers [superoxide anion (O2(•-)), thiobarbituric acid-reactive substances (TBARS) and advanced oxidation protein products (AOPP)] and antioxidative defense markers [superoxide dismutase (SOD), total sulfhydryl groups (-SH) and total antioxidant status (TAS)].

RESULTS

Increased plasma TBARS, TAS, SH groups levels and SOD activity were found in schizophrenic patients compared to control group. LA supplementation significantly reduced TBARS, AOPP and improved TAS levels in healthy subjects, while there were no significant differences in patients group. SH groups increased after 45 days and decreased to baseline levels after 90 days of supplementation in the control group. SOD activity decreased significantly in patients group after 45 days and 90 days of supplementation. After initial rose SOD activity in control group, decreased to baseline levels found after 90 days.

CONCLUSION

LA supplementation decreased lipid peroxidation and oxidative damage of proteins and improved non-enzymatic antioxidant capacity in healthy controls. No significant changes were observed on oxidative damage in patients with schizophrenia.

Effects of polyphenol-rich chokeberry juice on antioxidant/pro-oxidant status in healthy subjects

Berry fruits are a rich source of polyphenols, especially anthocyanins: well-known potent anti-oxidant phytochemicals. The purpose of this study was to evaluate beneficial effects of long-term consumption of polyphenol-rich organic chokeberry juice on different markers of antioxidant/pro-oxidant status in healthy female volunteers. Twenty-nine women, aged 25-49, were included in the study. Serological markers of oxidative stress and antioxidant defence, blood pressure, routine biochemical, and anthropometric parameters were analyzed at baseline and after twelve weeks of regular chokeberry juice consumption. Significant decrease in thiobarbituric acid-reactive substances level (TBARS; P<.001) and pro-oxidant-antioxidant balance (PAB; P<.05), as well as increase in paroxonase-1 activity toward diazoxon (P<.01) were found. Total oxidative status and sulphydryl groups levels were not significantly influenced by the intervention. Anthropometric, biochemical parameters, and blood pressure values were within the referent values for all subjects and were not influenced by the chokeberry juice consumption. However, we found positive correlation between age, body mass index, waist circumference, body fat percent, blood pressure, and analyzed marker of lipid peroxidation, which was influenced by the consumption. In conclusion, the fine modulation of several antioxidant/pro-oxidant status biomarkers observed in healthy subjects indicates putative prophylactic effects of polyphenol-rich chokeberry juice and supports its importance as part of an optimal diet.

Associations of oxidative stress status parameters with traditional cardiovascular disease risk factors in patients with schizophrenia

BACKGROUND

The purpose of this study was to assess oxidative stress status parameters and their possible associations with traditional cardiovascular risk factors in patients with schizophrenia, as well as their potential for patient-control discrimination.

METHODS

Fasting glucose, lipid profile and oxidative stress status parameters were assessed in 30 schizophrenic patients with atypical antipsychotic therapy and 60 control subjects.

RESULTS

Malondialdehyde (MDA), pro-oxidant/antioxidant balance (PAB) and total anti-oxidant status (TAS) were significantly higher whereas total sulfhydryl (SH) groups were significantly lower in schizophrenic patients vs. control group. Higher serum PAB values showed an independent association with schizophrenia. The addition of PAB to conventional risk factors improved discrimination between healthy control subjects and patients.

CONCLUSION

Increased oxidative stress and changed lipid profile parameters are associated in schizophrenic patients and may indicate risk for atherosclerosis. The serum PAB level may reflect the levels of oxidative stress in schizophrenia and improve discrimination of patients from controls.

Biomarkers of acute kidney injury in pediatric cardiac surgery

OBJECTIVES

Acute kidney injury (AKI) is a significant problem in children undergoing cardiopulmonary bypass (CPB). The aims of this study were to assess the diagnostic validity of serum CysC (sCysC), serum neutrophil gelatinase lipocalin (sNGAL), urine neutrophil gelatinase lipocalin (uNGAL), urine kidney injury molecule (uKIM)-1, and urine liver fatty acid-binding protein (uL-FABP) to predict AKI presence and severity in children undergoing CPB.

DESIGN AND METHODS

We performed a prospective single-center evaluation of sCysC, sNGAL, uNGAL, uKIM-1 and uL-FABP at 0, 2, 6, 24 and 48 h postoperatively in children undergoing CPB during cardiac surgery. AKI was defined as ≥25% decrease in the estimated creatinine clearance (eCCl) from pre-operative baseline at 48h after surgery.

RESULTS

Of the 112 patients, 18 patients (16.1%) developed AKI; four of them needed acute dialysis treatment and three AKI patients died. In the AKI compared to the non-AKI group, sCysC at 2h, and uNGAL and uL-FABP at 2-48 h were significantly increased, as well as CPB, aortic cross clamp time and length of hospital stay. Biomarkers increased with worsening AKI severity. At 2h after CPB the best accuracy for diagnosis of AKI had uL-FABP and sCysC with area under the receiver operator curve (AUC) of 0.89 and 0.73, respectively. At 6 and 24h after CPB the best AUC was found for uL-FABP (0.75 and 0.87 respectively) and for uNGAL (0.70 and 0.93, respectively).

CONCLUSIONS

sCysC, uNGAL and uL-FABP are reliable early predictors for AKI after CPB. By allowing earlier timing of injury and earlier intervention, they could improve AKI outcome.

Spectral Detection of Micro-Metastases and Individual Metastatic Cells in Lymph Node Histology

The detection of micro-metastases and individual metastatic cells in lymph node tissue by spectral methods is summarized. These methods are based on instrument-based acquisition of thousands of infrared spectra of individual tissue pixels from the tissue section, and analysis of the resulting spectral hypercube by multivariate algorithms. The method of infrared image acquisition, followed by multivariate analysis, is henceforth referred to as Spectral Histopathology (SHP). SHP produces pseudo-color images of tissue sections which reveal details that compare very favorably with images collected from hematoxylin/eosin (H & E) stained tissues in that the same tissue structures are detected. However, the infrared results are based on objective and reproducible measurements and do not depend on subjective interpretation. One of the major topics of this paper is the comparison of spectral patterns observed for the same cancer type from different patients. While this is easy in some tissue types, we found it to be difficult in tissues of very different cellularity, or tissue sections that exhibit high levels of inflammatory response. In both cases, spectral quality will be compromised due to confounding effects resulting from scattering effects. The correction of these effects now permits the direct comparison of different patient samples, and paves the way for diagnostic algorithms for cancer detection to be developed.

Synthesis and properties of hydroxyapatite/poly-L-lactide composite biomaterials

Calcium hydroxyapatite (HAp) and poly-L-lactide (PLLA) were synthesized chemically. The obtained HAp was of high purity and, after special thermal treatment, of high crystallinity as well. Synthesis of PLLA was performed using L-lactide as a monomer and nontoxic initiator. In this way a polymer of large molar weight (about 400,000) was obtained. The HAp and PLLA obtained were used as constituents of the HAp/PLLA composite biomaterial, a potential material for implants. The composite was obtained by mixing completely dissolved PLLA with granules of HAp. The composite was compacted by cold and hot pressing at pressures of 49.0-490.5 MPa and temperatures of 20-184 degrees C. The material obtained at optimum process parameters had a density of 99.6% and compressive strength of 93.2 MPa.

[Interactions of the most frequently used drugs in the treatment of angina pectoris]

It seems that knowledge and evaluation of drug-interactions with organic nitrates, beta-blockers and calcium-channel blockers are of great importance in relation to patients with chronic diseases, who usually take more than one drug, which is in conjunction with the effect of their ageing. Organic nitrates are safe and the most important drug-group in angina pectoris therapy. Beta-adrenoreceptor blocking agents and calcium-channel blockers are involved in interactions with many different drugs (twenty interactions), but only three interactions are evaluated as interactions of high clinical significance (adrenaline, cimetidine and anti-thyroid agents with beta-blockers, and anti-arrhythmic agents, beta-blockers and cyclosporin with calcium-channel blockers), while the others are of moderate or minimal significance. The most desired interactions of these drugs can be avoided: adjustment of dosage, avoidance of fixed-combination, use of adequate form of drug, or alternative drug and, if necessary, elimination of one drug from therapy. Knowledge of these drug-interactions is important for physician's routine practice either in primary health-care or in hospital conditions.

The in vivo metabolism of progestins. IV. The metabolic clearance rate and plasma binding of 6alpha-methylpregn-4-ene-3, 20-dione in women

[3H]6alpha-methylprogesterone (6MP) was synthesized by selective catalytic tritiation of the delta1-olefinic bond of 6alpha-methylpregna-1,4-diene-3,20-dione. The metabolic clearance rate of 6MP (MCR6MP) was determined in 6 women by the single injection technique. The plasma MCR6MP was 4047 +/- 298 L/day (59 +/- 15 L/day/kg) which was higher than the MCR of progesterone and medroxyprogesterone acetate (6alpha-methyl-17alpha-hydroxy-pregna-4-ene-3,20-dione acetate). The high clearance was not due to binding or metabolism of 6MP by red cells. Although 6MP was bound to CBG with a lower affinity than progesterone, this could not entirely explain the high MCR6MP. When considered with the reports of progesterone and medroxyprogesterone acetate clearance, the present studies suggest that the 6alpha-substitution of progesterone leads to an increased rate of steroid metabolism in women.

In vitro metabolism of progestins. III. The metabolic clearance rate of medroxyprogesterone acetate in monkeys

3H-medroxyprogesterone acetate (MPA) was synthesized by selective catalytic tritiation of the delta1-olefinic bond of 6alpha-methyl-17alpha-hydroxy-pregna-1,4-diene-3,20-dione acetate. The metabolic clearance rate of MPA (MCRMPA) was determined in 9 female Rhesus monkeys by the single injection technique. The blood MCRMPA was 201 +/- 19 L/day (42.2 +/- 4.0 L/day/kg) which was approximately the same as that reported for progesterone clearance in the monkey. We conclude that a greater biological activity of MPA compared to progesterone cannot be related to its prolonged retention in the blood. Although both MPA and amino-glutethimide alter the rate of steroid metabolism in some species, neither of these agents influences the metabolic clearance rate of 3H-MPA in the monkey.

A novel affinity column for isolation of androgen binding protein from rat epididymis

An androgen affinity column was synthesized by covalently linking 3-oxo-17beta-hydroxy-5alpha-androstan-17alpha-(6-hexanoic acid) to cyanogen bromide activated Sepharose through a dipropyldiamine side arm. This column was designed to recover androphilic proteins from homogenates rich in nonspecific esterases. An extract of rat epididymis was adsorbed on the affinity column after partial purification by ammonium sulfate precipitation. The column was washed with 1 M KCl and the androgen binding protein eluted with 17beta-hydroxy-5alpha-androstan-3-one resulting in a 1,100-fold increase in specific activity. This protein had the same mobility on polyacrylamide gels and the same estimated molecular weight (135,000 daltons by gel filtration) as androgen binding protein in the original extract. By contrast, electrophoresis on sodium dodecyl sulfate containing gels yielded 2 bands with estimated molecular weights of 42,000 and 47,000 daltons. These observations are consistent with a subunit structure for rat epididymal androgen binding protein.

The in vivo metabolism of progestins. I. The metabolic clearance rates of progesterone and medroxyprogesterone acetate in the dog

[3H]Medroxyprogesterone acetate (MPA) was synthesized by selective catalytic tritiation of the delta1-olefinic bond of 6alpha-methyl-17alpha-hydroxy-pregn-1,4-diene-3,20 dione acetate. [14C]MPA was synthesized by acetylation of 6alpha-methyl-17alpha-hydroxy-pregn-4-ene-3,20-dione with [14C]acetic anhydride. These radioactive materials were used to determine the MPA metabolic clearance rates (MCRMPA)and volumes of distribution (VoMPA) in dogs by the single injection technique. The metabolism of progesterone was also studied in the same animals. The MCRMPA (696 +/- 51 l/day) was only one-half that of progesterone (1332 +/- 59). By contrast, the volumes of distribution for the two steroids were similar. The metabolic clearance rates and the volumes of distribution for MPA and progesterone did not change during treatment with amino-glutethimide, a drug which is known to alter steroid metabolism in man.

Medroxyprogesterone acetate: a steroid with potent progestational activity but low receptor affinity in the guinea pig uterus

The guinea pig progestin receptor appears to be unique among mammalian receptors studied to date in that it displays a low binding affinity for some biologically potent 17 alpha-substituted progestinss. [3H]Medroxyprogesterone acetate (MPA) was synthesized and used to investigate this dichotomy between binding affinity and biological activity. The comparison of cytoplasmic and nuclear receptor binding characteristics suggested that progesterone and MPA were bound to the same receptor but with different affinities. Following an intravenous injection of 3H-steroids, the plasma level of progesterone was lower than that of MPA at all time points. Correspondingly, for up to 6 hours following steroid administration, progesterone levels were lower in uterine cytoplasm and higher in nuclei than those of MPA. However, by 24 hours, MPA nuclear levels were higher than those of progesterone, in accordance with plasma levels. We conclude that the potent biological activity of MPA relative to progesterone is due in part to its slower rate of metabolism and longer nuclear retention.