Fractional calculus as a generalized kinetic model for biochemical methane potential tests

This study presents a fractional calculus model as a generalized kinetic model for estimating the maximum methane yield and degradation kinetics in biomethane potential (BMP) assays, a key analytical method in anaerobic digestion research and application. The fractional model outperformed common first-order kinetic models by yielding superior data fitting and properly managing substrate heterogeneity. The fractional model showed robust performance in mono-digestion, co-digestion and pre-treatment BMP assays with or without presence of large tailing or sigmoidal patterns in the BMP curve. The main advantage of the fractional model over other models is its ability to capture the complexities of the methane production process without losing model accuracy. Assessment of the mathematical model revealed that for fractional orders greater than 0.8 the Mittag-Leffler sequence could be transformed into a more computationally efficient exponential function.

Identification of housekeeping genes for microRNA expression analysis in kidney tissues of Pkd1 deficient mouse models

Polycystic kidney disease is a complex clinical entity which comprises a group of genetic diseases that leads to renal cyst development. We evaluated the most suitable housekeeping genes for microRNA expression by RT-qPCR analyses of kidney tissues in Pkd1-deficient mouse models from a panel of five candidates genes (miR-20a, miR-25, miR-26a, miR-191 and U6) and 3 target genes (miR-17, miR-21 and let-7a) using samples from kidneys of cystic mice (Pkd1^flox/flox:Nestin^cre, CY), non-cystic controls (Pkd1^flox/flox, NC), Pkd1-haploinsufficient (Pkd1^+/−, HT), wild-type controls (Pkd1^+/+, WT), severely cystic mice (Pkd1^V/V, SC), wild-type controls (CO). The stability of the candidate genes was investigated using NormFinder, GeNorm, BestKeeper, DataAssist, and RefFinder software packages and the comparative ΔCt method. The analyses identified miR-26a as the most stable housekeeping gene for all kidney samples, miR-20a for CY and NC, miR-20a and miR-26a for HT and WT, and miR-25 and miR-26a for SC and CO. Expression of miR-21 was upregulated in SC compared to CO and trends of miR-21 upregulation and let-7a downregulation in CY and HT compared to its control kidneys, when normalized by different combinations of miR-20a, miR-25 and miR-26a. Our findings established miR-20a, miR-25, and miR-26a as the best housekeeping genes for miRNA expression analyses by RT-qPCR in kidney tissues of Pkd1-deficient mouse models.

Can a Proper T-Cell Development Occur in an Altered Thymic Epithelium? Lessons From EphB-Deficient Thymi

For a long time, the effects of distinct Eph tyrosine kinase receptors and their ligands, ephrins on the structure, immunophenotype, and development of thymus and their main cell components, thymocytes (T) and thymic epithelial cells (TECs), have been studied. In recent years, the thymic phenotype of mutant mice deficient in several Ephs and ephrins B has been determined. Remarkably, thymic stroma in these animals exhibits important defects that appear early in ontogeny but little alterations in the proportions of distinct lymphoid cell populations. In the present manuscript, we summarize and extend these results discussing possible mechanisms governing phenotypical and functional thymocyte maturation in an absence of the critical T-TEC interactions, concluding that some signaling mediated by key molecules, such as MHCII, CD80, β5t, Aire, etc. could be sufficient to enable a proper maturation of thymocytes, independently of morphological alterations affecting thymic epithelium.

Eph/Ephrins-Mediated Thymocyte-Thymic Epithelial Cell Interactions Control Numerous Processes of Thymus Biology

Numerous studies emphasize the relevance of thymocyte-thymic epithelial cell (TECs) interactions for the functional maturation of intrathymic T lymphocytes. The tyrosine kinase receptors, Ephs (erythropoietin-producing hepatocyte kinases) and their ligands, ephrins (Eph receptor interaction proteins), are molecules known to be involved in the regulation of numerous biological systems in which cell-to-cell interactions are particularly relevant. In the last years, we and other authors have demonstrated the importance of these molecules in the thymic functions and the T-cell development. In the present report, we review data on the effects of Ephs and ephrins in the functional maturation of both thymic epithelial microenvironment and thymocyte maturation as well as on their role in the lymphoid progenitor recruitment into the thymus.

3D immunofluorescence analysis of early thymic morphogenesis and medulla development

The thymus represents an epithelial microenvironment specialized in the generation of T-cells. The mechanisms or signals that determine the initial differentiation of the two well distinguished histological compartments of the thymus, cortex and medulla, remain unknown. Here, we report a three-dimensional analysis of the distribution of some established thymic epithelial markers in relation to thymic anatomical development during the first steps of thymus organogenesis. In the thymic primordium, initial lumen is lined by claudin (Cld)3/4+K5+ cells, after thymus growth and lobulation they form a continuous branched structure that increases its length and branching degree. Within it, the presence of luminal structures can be distinguished, even at E13.5. The medullary marker mouse thymic stroma 10 (MTS10) is upregulated in these Cld3/4+ lumen forming cells in a proximal-distal sequence. This structural organisation is histologically similar to that described in other epithelial organs undergoing a branching morphogenesis process. These results indicate that the thymic medulla can be evidenced as a continuous branched structure from early stages and suggest a thymic developmental program based on or containing elements of a branching morphogenesis program modified by the presence of lymphoid cells, in which medullary epithelial cell commitment is initially determined by lumen formation.

Diffusion-reaction model for Drosophila embryo development

During the early stages of gastrulation in Drosophila embryo, the epithelial cells composing the single tissue layer of the egg undergo large strains and displacements. These movements have been usually modelled by decomposing the total deformation gradient in an (imposed or strain/stress dependent) active part and a passive response. Although the influence of the chemical and genetic activity in the mechanical response of the cell has been experimentally observed, the effects of the mechanical deformation on the latter have been far less studied, and much less modelled. Here, we propose a model that couples morphogen transport and the cell mechanics during embryogenesis. A diffusion-reaction equation is introduced as an additional mechanical regulator of morphogenesis. Consequently, the active deformations are not directly imposed in the analytical formulation, but they rather depend on the morphogen concentration, which is introduced as a new variable. In this study, we show that strain patterns similar to those observed during biological experiments can be reproduced by properly combining the two phenomena. In addition, we use a novel technique to parameterise the embryo geometry by solving two Laplace problems with specific boundary conditions. We apply the method to two morphogenetic movements: ventral furrow invagination and germ band extension. The matching between our results and the observed experimental deformations confirms that diffusion-reaction of morphogens can actually be controlling large morphogenetic movements.

Endovascular treatment of hemoptysis by abnormal systemic pulmonary artery supply

We report the case of a 29-year-old man with hemoptysis. The patient came to the emergency department, where a laboratory test and chest radiograph were reported as normal. The following day the patient again had hemoptysis, though less than previously. He reported no chest pain, dyspnea, fever, catarrh, changes in urine or feces, contact with patients with bacillus disease or constitutional symptoms. Doppler ultrasound of the chest showed right basal parenchymatous condensation containing a vessel with arterial flow (in the opposite direction to the aortic flow) compatible with an aberrant vessel, possibly a sequestration, leaving the aorta above the celiac trunk. Because of the findings of the chest echogram and magnetic resonance study, thoracoabdominal computed tomography angiography was undertaken; this showed right basal condensation and an anomalous vessel originating 1 cm above the celiac trunk, supplying the right lower lobe. An aortic and pulmonary arteriogram via an arterial and right femoral vein approach confirmed the findings. The patient was treated successfully with percutaneous embolization with coils. The relevant literature is reviewed.

Alterations in the thymocyte phenotype of EphB-deficient mice largely affect the double negative cell compartment

In the present study, we have analysed the phenotype of EphB2 and/or EphB3 deficient thymocytes confirming and extending previous studies on the role of this family of molecules in T-cell differentiation. In all mutant thymuses statistically significant reduced cell contents were observed. This reduction of thymic cellularity correlated with increased proportions of apoptotic cells, largely both double negative (DN; CD4- CD8-) and double positive (CD4+ CD8+) cells, and decreased proportions of DN cycling cells. Adult deficient thymuses also showed increased proportions of DN cells but not significant variations in the percentages of other thymocyte subsets. In absolute terms, the thymocyte number decreased significantly in all thymocyte compartments from the DN3 (CD44- CD25+) cell stage onward, without variations in the numbers of both DN1 (CD44+ CD25-) and DN2 (CD44+ CD25+) cells. Remarkably, all these changes also occurred from the 15-day fetal EphB2 and/or EphB3 deficient mice, suggesting that adult phenotype results from the gradual accumulations of defects appearing early in the thymus ontogeny. As a reflection of thymus condition, a reduction in the number of T lymphocytes occurred in the peripheral blood and mesenteric lymph nodes, but not in spleen, maintaining the proportions of T-cell subsets defined by CD4/CD8 marker expression, in all cases.

Adult patent ductus arteriosus: treatment with a stent-graft

We present the case of a 63-year-old woman with a short patent ductus arteriosus and aneurysmal pulmonary arteries who was treated by placement of a stent-graft. The technique proved simple and safe. Further research is required to improve the design of stent-grafts and their release system for use of this technique in adult patients with this disorder.

Psychological risk and protective factors for antisocial behavior in adolescents

The aim of this paper is to analyze the influence and differential weight of some specific psychological variables on adolescent antisocial behavior. A sample of 1,851 adolescents (49.92 % men and 50.08 % women) from the Autonomous Community of Madrid was assessed. Several stepwise regression analyses were conducted, considering three different age groups (14-15, 16 and 17-18 years), with the criterion variables and the results showed that the main psychological risk factors associated with antisocial behavior were variables linked to sensation seeking construct (impulsiveness, disinhibition, excitement seeking, etc.), while the protective factors identified were variables such as empathy and religious practices. The age groups were considered, keeping a design of optimum prevention programs with psychological character in mind.

Differential interaction of the tyrosine phosphatases PTP-SL, STEP and HePTP with the mitogen-activated protein kinases ERK1/2 and p38alpha is determined by a kinase specificity sequence and influenced by reducing agents

The protein tyrosine phosphatases (PTPs) PTP-SL, STEP and HePTP are mitogen-activated protein kinase (MAPK) substrates and regulators that bind to MAPKs through a kinase-interaction motif (KIM) located in their non-catalytic regulatory domains. We have found that the binding of these PTPs to the MAPKs extracellular-signal-regulated kinase 1 and 2 (ERK1/2), and p38alpha is differentially determined by the KIM-adjacent C-terminal regions of the PTPs, which have been termed kinase-specificity sequences, and is influenced by reducing agents. Under control conditions, PTP-SL bound preferentially to ERK1/2, whereas STEP and HePTP bound preferentially to p38alpha. Under reducing conditions, the association of p38alpha with STEP or HePTP was impaired, whereas the association with PTP-SL was unaffected. On the other hand, the association of ERK1/2 with HePTP was increased under reducing conditions, whereas the association with STEP or PTP-SL was unaffected. In intact cells, PTP-SL and STEP distinctively regulated the kinase activity and the nuclear translocation of ERK1/2 and p38alpha. Our results suggest that intracellular redox conditions could modulate the activity and subcellular location of ERK1/2 and p38alpha by controlling their association with their regulatory PTPs.

Two clusters of residues at the docking groove of mitogen-activated protein kinases differentially mediate their functional interaction with the tyrosine phosphatases PTP-SL and STEP

Regulated function of mitogen-activated protein (MAP) kinases involves their selective association through docking sites with both activating MAP kinase kinases and inactivating phosphatases, including dual specificity and protein-tyrosine phosphatases (PTP). Site-directed mutagenesis on the mammalian MAP kinases ERK2 and p38alpha identified within their C-terminal docking grooves two clusters of residues important for association with their regulatory PTPs, PTP-SL and STEP. ERK2 and p38alpha mutations that resembled the sevenmaker gain-of-function mutation in the Rolled D. melanogaster ERK2 homologue failed to associate with PTP-SL, were not retained in the cytosol, and were poorly inactivated by this PTP. Additional ERK2 mutations at the docking groove showed deficient association and dephosphorylation by PTP-SL, although their cytosolic retention was unaffected. Other ERK2 mutations, resembling gain-of-function mutations in the FUS3 yeast ERK2 homologue, associated to PTP-SL and were inactivated normally by this PTP. Our results demonstrate that mutations at distinct regions of the docking groove of ERK2 and p38alpha differentially affect their association and regulation by the PTP-SL and STEP PTPs.

Stromal cell-derived factor 1/CXCR4 signaling is critical for early human T-cell development

The present study investigated the potential role of stromal cell-derived factor 1 (SDF-1) in human intrathymic T-cell differentiation. Results show that SDF-1 is produced by human thymic epithelial cells from the subcapsular and medullary areas, and its receptor, CXCR4, is up-regulated on CD34(+) precursor cells committed to the T-cell lineage. Chimeric human-mouse fetal thymus organ culture (FTOC) seeded with purified CD34(+) thymic progenitors and treated with neutralizing antibodies against SDF-1 or CXCR4 showed a significant reduction of the number of human thymocytes and an arrested thymocyte differentiation in the transition between CD34(+) precursor cells and CD4(+) immature thymocytes. SDF-1-treated FTOC showed an increase of human thymocyte numbers, mainly affecting the most immature subpopulations. Moreover, these results suggest that CXCR4/SDF-1 signaling is not critical for the CD34(+) cell precursor recruitment to the thymus. On the other hand, SDF-1 significantly increased the viability of CD34(+) T-cell precursors modulating the expression of BCL-2 and BAX genes, and stimulated the proliferation of CD34(+) thymic precursor cells, particularly in synergy with interleukin 7 (IL-7), but not with other cytokines, such as stem cell factor or flt3-ligand. Accordingly, only IL-7 was able to up-regulate CXCR4 expression on CD34(+) thymic progenitors. In addition, deprivation of SDF-1 partially inhibited human thymocyte expansion induced by IL-7 in human-mouse FTOC. This study indicates that SDF-1/CXCR4 signaling is required for the survival, expansion, and subsequent differentiation of human early thymocytes and identifies a new mechanism by which IL-7 mediates its effects on human thymopoiesis.

Delineation of intrathymic T, NK, and dendritic cell (DC) progenitors in fetal and adult rats: demonstration of a bipotent T/DC intermediate precursor

We previously published study results stating that the early rat fetal liver contains a high frequency of T/dendritic cells (DCs), but rarely T/NK bipotent common progenitors. Now, by using xenogenic rat/SCID mouse fetal thymic organ cultures, we extend these observations to the thymus, in which conflicting data have been published in human and mouse. On the one hand, enriched adult intrathymic CD45+CD2- triple negative for CD8, CD4, and CD3 Ag cell progenitors, which contained both rearranged TCRbeta chain and pre-Talpha chain transcripts, completely lacked NKR-P1A expressing cells, and upon limiting dilution conditions, generated T- and T/DC-containing lobes, but no T/NK or NK ones were found. On the other hand, the CD45+CD2- triple negative for CD8, CD4, and CD3 Ags cell population obtained from 15- and 16-day-old fetal rat thymus can be divided into NKR-P1A- and NKR-P1A(low) cell subpopulations that differ in several aspects. Both cell subsets expressed pre-TCRalpha chain transcripts, but only the former contained fully rearranged TCRbeta chain transcripts. Upon limiting dilution, T cell-committed progenitors were only found in the NKR-P1A- cell population, whereas NK-committed progenitors were present in the NKR-P1A(low) population. More importantly, bipotential T/NK progenitors were very rare and were found only in the NKR-P1A(low) cell population, whereas bipotential T/DC progenitors, only previously suggested in the adult mouse thymus, were observed frequently in the NKR-P1A-CD2- cell subpopulation. Our results demonstrate, therefore, that a common intrathymic T/DC intermediate represents the main T cell developmental pathway in rat thymus.

Distinct mechanisms contribute to generate and change the CD4:CD8 cell ratio during thymus development: a role for the Notch ligand, Jagged1

In adult life, the high CD4:CD8 cell ratio observed in peripheral lymphoid organs originates in the thymus. Our results show that the low peripheral CD4:CD8 cell ratio seen during fetal life also has an intrathymic origin. This distinct production of CD4(+)CD8(-) and CD4(-)CD8(+) thymocytes is regulated by the developmental age of the thymic stroma. The differential expression of Notch receptors and their ligands, especially Jagged1, throughout thymus development plays a key role in the generation of the different CD4:CD8 cell ratios. We also show that the intrathymic CD4:CD8 cell ratio sharply changes from fetal to adult values around birth. Differences in the proliferation and emigration rates of the mature thymocyte subsets contribute to this change.

Role of glucocorticoids in early T-cell differentiation

The results of the T-cell differentiation in the progeny of adrenalectomized pregnant rats (Adx fetuses), an experimental model that ensures the absence of glucocorticoids (GCs) during the first stages of development, are summarized. In Adx thymuses there is an accelerated maturation of thymocytes that is reversed by in vivo GC replacement. In addition, Adx thymuses show decreased cell content, which correlates with both the increased numbers of apoptotic cells and an early migration of DP (CD4+CD8+) and SP (both CD4+CD8- and CD4-CD8+) thymocytes to the spleen. As shown by in vitro recolonization assays, accelerated T-cell differentiation is a consequence of changes in the biology of lymphoid precursors occurring in the fetal liver of Adx fetuses. They arrive at the thymic primordium earlier and mature faster than the fetal liver lymphoid progenitors from Sham control fetuses. After the establishment of a fetal hypothalamus-pituitary-gland-adrenal-gland (HPA) axis, there is a gradual normalization of the T-cell development Adx fetuses.

Early T cell development can be traced in rat fetal liver

The degree of T cell commitment reached by cell precursors present in the fetal liver is a controversial issue. In the present work, the occurrence of fully T cell-committed progenitors among CD45+Thy-1+CD44+ 13-day-old rat fetal liver cells was demonstrated when limiting numbers of these cells in vitro reconstituted SCID mouse fetal thymic lobes providing single lineage-containing lobes for T, natural killer or dendritic cells. In addition, expression of rat pre-TCRalpha chain mRNA was detected in the CD45+ but not in the CD45- fetal liver cells and fully rearranged TCR VBeta8-Cbeta mRNA transcripts were specifically detected in the former population, demonstrating early transcription of some rearranged TCRVBeta genes in the rat fetal liver of 13 days of gestation. Finally, fetal liver organ cultures provided low numbers of TCR gamma delta T cells and CD2+CD8+NKR-P1A- intracytoplasmic CD3+ immature T cells, which intracellularly reacted with a mAb specific to the TCRalpha Beta molecule. These results prove T, NK and DC cell lineage determination at a prethymic stage in the fetal liver.

Early maturation of T-cell progenitors in the absence of glucocorticoids

In the present work, we demonstrated that both fetal liver and thymic T-cell precursors express glucocorticoid receptors (GRs) indirectly suggesting a role for glucocorticoids (GCs) in the earliest events of T-cell differentiation. To evaluate this issue, we analyzed the thymic ontogeny in the progeny of adrenalectomized pregnant rats (Adx fetuses), an in vivo experimental model, which ensures the absence of circulating GCs until the establishment of the fetal hypothalamus-pituitary-adrenal (HPA) axis. In the absence of maternal GCs, T-cell development was significantly accelerated, the process being reversed by in vivo GC replacement. Mature single positive thymocytes (both CD4 and CD8) appeared in 16-day old fetal Adx thymus when in the control fetuses, most thymocytes still remained in the double-negative (DN) CD4(-)CD8(-) cell compartment. In addition, emigration of T-cell receptor (TcR)alphabeta positive cells to the spleen also occurred earlier in Adx fetuses than in control ones. In vitro recolonization of cultured deoxiguanosine-treated mouse fetal thymus lobes with 13-day-old fetal liver cell suspensions from both Adx and control fetuses demonstrated changes in the developmental capabilities of fetal liver T-cell precursors from embryos grown in the absence of GCs. Furthermore, a precocious lymphoid colonization of the thymic primordium from Adx fetuses was evidenced by ultrastructural analysis of both Adx and Sham early thymus. Both findings accounted for the accelerated T-cell differentiation observed in Adx fetuses. Together, these results support a role for GCs not only in the thymic cell death, but also in the early steps of T-cell differentiation.

Glucocorticoid-mediated regulation of thymic dendritic cell function

The possible effects of glucocorticoids (GC) on the biology of thymic dendritic cells (DC) have been analyzed. Both DC and GC seem to be involved in intrathymic T cell selection but possible relationships, if any, between them remain currently unknown. For the first time, we have proved the expression of GC receptors in thymic DC. Moreover, our data demonstrate that in vitro dexamethasone (Dex) treatment barely affects the viability of mature thymic DC, which are largely resistant to its apoptotic effect. Dex-treated thymic DC also show a slightly reduced surface expression of some adhesion and co-stimulatory molecules in correlation with diminished allostimulatory properties. Furthermore, the production of both IL-1beta and tumor necrosis factor (TNF)-alpha, but not that of IL-6 and IL-10, diminished in the mixed leukocyte reaction established with Dex-treated thymic DC. However, the addition of recombinant rat IL-1beta and TNF-alpha, alone or in combination, did not recover the allostimulatory capacity. Taken together, these results support certain GC-mediated regulation of the activity of thymic DC which could be relevant for the biology of the thymus gland.

Interleukin-7 treatment promotes the differentiation pathway of T-cell-receptor-alpha beta cells selectively to the CD8+ cell lineage

In this report we have studied the influence of interleukin-7 (IL-7) on thymocyte differentiation by evaluating the effects of IL-7 on the generation of T-cell receptor-alpha beta (TCR-alpha beta) and TCR-gamma delta thymocyte subpopulations in rat fetal thymus organ culture. IL-7 enhanced the differentiation pathway of TCR alpha beta thymocytes, first increasing the numbers of immature CD8+ cells, and later those of both CD4+ CD8+ and mature thymocytes. The kinetics of thymocyte migration out of thymic lobes was also accelerated, and the average number of mature TCR-alpha beta phi emigrants per day was increased in the presence of IL-7. Moreover, mature CD4- CD8+ thymocytes were preferentially generated after IL-7 administration. This TCR-alpha beta hi cell population was not actively dividing, indicating that IL-7-promoted thymocyte differentiation was selective to the CD8 cell lineage. Distribution of some TCR-V alpha and TCR-V beta segments among mature thymocytes was also modified in IL-7-treated thymic lobes. On the contrary, the maturation of TCR-gamma delta was not affected by IL-7 addition during the first days of culture, but their numbers sharply increased by day 6 of culture. These results were confirmed with IL-7-treated cultures for 24 hr, showing that IL-7 responsiveness was acquired by TCR-gamma delta cells late in thymus ontogeny. The present results thus indicate a key role for IL-7 in the maturation of TCR-alpha beta thymocytes and the expansion of thymic TCR-gamma delta cells.

CYP2D6 genotypes in Spanish women with breast cancer

Wild type and three mutated alleles of the polymorphic CYP2D6 gene were studied in genomic DNA samples from 187 women with breast carcinoma and 151 healthy women by a mutation-specific polymerase chain reaction. The prevalence of the enzyme-inactivating CYP2D6(B) allele was higher among patients (18.2%) than in controls (11.6%; OR = 1.7; 95% c.i. = 1.14-3.13; P = 0.018). This excess was more marked in postmenopausal patients (19.8%, P = 0.0086) and in patients with non-ductal infiltrating carcinomas (25.8%, P = 0.003). The percentage of carriers of only one active gene (heterozygote extensive metabolizers) was higher in patients (31% vs. 19.9%; OR = 1.81; 95% c.i. = 1.06-3.11; P = 0.02). The CYP2D6(B)-carrier state may be related to a greater risk of breast cancer in women.

Effect of zinc or S-adenosyl-l-methionine on long term administration of low doses of lead to rats

Two alternatives for the treatment of lead intoxication, administration of zinc or a thiol donor, S-adenosyl-L-methionine (SAM), were analysed. Rats were exposed to lead (Pb)-acetate (60 mg/l) in drinking water during 90 days; one group also received SO4Zn in water (40 mg/l), while another received both Pb and SAM (5 mg/24 hr intraperitoneally. Erythrocytic delta-aminolaevulinic dehydratase (ALA-D) activity was significantly reduced (P < 0.001) both in rats receiving Pb alone and in rats receiving Pb and each of the other two treatments. The high erythrocytic uroporphyrinogen synthetase (URO-S) activity noticed in Pb administered rats, was significantly (P < 0.001) reduced in animals treated either with zinc or with SAM. Hepatic ALA-D activity tended to decrease while renal enzyme activity was not modified by the low level Pb exposure used in this work. Interestingly, SAM treated rats in both tissues exhibited significantly (P < 0.01) higher activities of the enzyme. It is argued that SAM treatment causes a surplus of thiols that allows the full expression of ALA-D catalytic activity.

Polymorphic oxidation of debrisoquine in lung cancer patients

Oxidative polymorphism of debrisoquine (DBQ) was assessed in 84 patients (81 male) with histologically proven bronchogenic carcinoma and in 143 healthy male smokers. 80 (95%) patients and 133 (93%) controls, with a metabolic ratio (MR) below 12.6, were classified as extensive metabolisers of DBQ (no significant difference between patients and controls). Only 1 of the 73 patients with epidermoid or microcytic carcinomas was classified as a poor metaboliser (PM) (P = 0.031 compared with controls). 63 patients (75%) and 110 controls (77%) showed a very fast oxidative rate, with MR values under 1 (not significant). The EM phenotype of DBQ might be a secondary genetic risk factor for developing bronchogenic carcinoma in male smokers.

Polymorphic oxidation of debrisoquine in women with breast cancer

Oxidative polymorphism of debrisoquine (DBQ) was determined in 98 women with breast cancer (mean age 59.2 years, SD 10.7; 18 were premenopausal when diagnosed), and in 446 healthy control women (mean age 25.4 years, SD 9.15). All of them were free of drug interactions with oxidation of DBQ. Ten patients (10.2%), all of them postmenopausal when diagnosed, and 423 controls (5.2%), with values for metabolic ratio of DBQ greater than 12.6, were classified as poor metabolizers (PM) of DBQ (p = 0.006). Relative risk for developing breast cancer among women with PM phenotype was 2.09 (95% confidence limits 0.97-4.48). The PM status of DBQ might be a secondary risk factor for breast cancer in postmenopausal women.

The effect of clobazam on steady state plasma concentrations of carbamazepine and its metabolites

Steady state metabolite/parent drug plasma ratios were measured in 15 epileptic patients on carbamazepine (CBZ) monotherapy and in seven patients treated with CBZ and clobazam (CLB). CBZ plasma concentrations did not differ between the two groups but patients also treated with CLB exhibited higher concentrations of CBZ-10,11-epoxide (CBZ-E) and trans-10,11-dihydro-10,11-dihydroxy-CBZ (CBZ-T). Ratios between all of the metabolites of CBZ and the parent compound were higher in patients on polytherapy but the ratio between metabolites was not different. CLB comedication causes a moderate increase (about 1.5-fold) in CBZ metabolism, probably by inducing its epoxidation.

Polymorphic oxidation of debrisoquine in bladder cancer

The oxidative polymorphism of debrisoquine has been determined in 125 patients with bladder cancer and in 556 healthy control subjects; 96.6% of patients and 93.9% of controls with a metabolic ratio of debrisoquine less than 12.6 were classified as extensive metabolizers of debrisoquine (P = NS). The distribution of frequencies of metabolic ratio values tended to have lower values in the patients (P less than 0.05), reflecting a higher oxidative rate of debrisoquine in urothelioma patients that cannot be explained solely in terms of enzymatic induction by drugs, tobacco or alcohol. Patients with a high occupational risk for urothelioma had lower metabolic ratio values (P = 0.03). Our results suggest that oxidative polymorphism of debrisoquine might be related to the pathogenesis of bladder cancer.

Desferrioxamine in the treatment of porphyria cutanea tarda: ineffectiveness of intramuscular administration

Four patients suffering from porphyria cutanea tarda received intramuscularly 10-15 g per month of desferrioxamine for periods ranging between 21 and 50 months. Porphyrin excretion was serially analyzed during this treatment. Desferrioxamine administration did not induce remission of the disease, which was subsequently achieved after treatment either with phlebotomies or chloroquine. Therefore, chronic intramuscular administration of desferrioxamine alone is ineffective in porphyria cutanea tarda.

Oxidative polymorphism of debrisoquine in Parkinson's disease

Oxidative phenotype and metabolic ratio (MR) of debrisoquine (DBQ) have been determined in 87 patients with Parkinson's disease and in 556 healthy control subjects. Three patients (3.45%) and 34 control subjects (6.12%), having an MR greater than 12.6, were classified as poor metabolisers (PM) of DBQ (ns). The distribution of MR values in the 84 Parkinsonian patients classified as extensive metabolisers (EM) showed a less efficient oxidative rate when compared with controls of the same phenotype (p less than 0.001). This difference may be due to enzymatic inhibition caused by drug treatment in 40 of these patients. As in patients not taking any drug known to inhibit the oxidation of DBQ, distribution of MR values was not different from that in controls. A negative correlation (r = -0.36, p less than 0.02) was found between MR of DBQ and age at onset of disease in patients free of drugs known to interact with DBQ metabolism. A higher rate of DBQ oxidation could be a genetic factor that delays the clinical onset of Parkinson's disease in predisposed people.

Photodynamic and non-photodynamic action of several porphyrins on the activity of some heme-enzymes

The action of porphyrins, uroporphyrin I and III (URO I and URO III), pentacarboxylic porphyrin I (PENTA I), coproporphyrin I and III (COPRO I and COPRO III), protoporphyrin IX (PROTO IX) and mesoporphyrin (MESO), on the activity of human erythrocytes delta-aminolevulinic acid dehydratase, porphobilinogenase, deaminase and uroporphyrinogen decarboxylase in the dark and under UV light was investigated. Both photoinactivation and light-independent inactivation was found in all four enzymes using URO I as sensitizer. URO III had a similar action as URO I on porphobilinogenase and deaminase and PROTO IX exerted equal effect as URO I on delta-aminolevulinic acid dehydratase and uroporphyrinogen decarboxylase. Photodynamic efficiency of the porphyrins was dependent on their molecular structure. Selective photodecomposition of enzymes by URO I, greater specificity of tumor uptake by URO I and enhanced porphyrin synthesis by tumors from delta-aminolevulic acid, with predominant formation of URO I, underline the possibility of using URO I in detection of malignant cells and photodynamic therapy.

Acetylator polymorphism in Parkinson's disease

Acetylator phenotype has been determined using sulphamethazine in 100 patients with Parkinson's disease and in 93 age-matched normal control subjects. Sixty-nine patients and 54 control subjects were classified as slow acetylators (NS). No relation was found among acetylator polymorphism and age at onset or clinical stage of disease. Amongst slow acetylators, the percentage of acetylated sulphamethazine in plasma was significantly lower in patients than in controls. Despite this finding, the results do not support any relationship between acetylator polymorphism and the risk of developing Parkinson's disease.

Hepatic acetylator polymorphism in breast cancer patients

Hepatic acetylator phenotype has been determined, using sulfamethazine, in 81 white Spanish women with histologically proven breast cancer and in 75 adequate female controls. No differences were detected in the distribution of acetylator phenotype between the two groups of slow acetylators, 49 patients (60.5%) and 45 controls (60%). The percentage of acetylated sulfamethazine in plasma for each phenotype was not different either. Our results suggest that there is no relationship between the hepatic acetylator polymorphism and the risk of developing breast cancer in women.

Studies on in vitro formation of complexes between porphyrins and chloroquine

Gel filtration and spectrophotometric studies revealed that uroporphyrin, heptacarboxylic-, and pentacarboxylic-porphyrins form in vitro complexes with chloroquine.

Patterns of porphyrin-excretion in female estrogen-induced porphyria cutanea tarda

It has been suggested that the urinary profile of porphyrins excreted by female patients with estrogen-induced porphyria cutanea tarda is peculiar in that heptacarboxylic porphyrin equals or exceeds uroporphyrin. The chromatographic pattern of urinary porphyrin excretion was studied in nine females with porphyria cutanea tarda precipitated by estrogens, 129 porphyric males, and nine females, whose porphyria was not hormone-induced. Both female porphyric groups showed absolutely the same urinary chromatographic pattern and looked quite similar to the pattern observed in male patients. None of our female porphyric patients, whether treated with estrogens or not, showed percentage values for the heptacarboxylic porphyrin higher or equal to the uroporphyrin values. Our results do not support the hypothesis that the profile of urinary porphyrin excretion found in estrogen-induced porphyria cutanea tarda is atypical.