RESUMEN
Increasing evidence highlights the role of the ATP synthase/hydrolase, also known as F1FO-complex, as key molecular and enzymatic switch between cell life and death, thus increasing the enzyme attractiveness as drug target in pharmacology. Being inhibition of ATP production usually linked to antiproliferative properties, drugs targeting the enzyme complex have been mainly considered to fight pathogen parasites and cancer. In recent years, a number of natural macrolides, produced by bacterial fermentation and structurally related to the classical enzyme inhibitor oligomycin, have been shown to bind to the membrane-embedded FO sector and to inhibit the enzyme complex by an oligomycin-like mechanism, namely by interacting with the c-ring. Other than natural macrolide antibiotics, which display variegated inhibition power on different F1FO-complexes, synthetic compounds from the diarylquinoline and organotin families also target the c-ring and strongly inhibit the enzyme. Bioinformatic insights address drug design to target FO subunits. Additionally, the possible modulation of the drug inhibition power, by amino acid substitutions or post-translational modifications of c-subunits, adds further interest to the target. The present survey on compounds targeting the c-ring and bi-directionally blocking the transmembrane proton flux which drives ATP synthesis/hydrolysis, discloses new therapeutic options to fight cancer and infections sustained by therapeutically recalcitrant microorganisms. Additionally, c-ring targeting compounds may constitute new tools to eradicate undesired biofilms and to address at the molecular level the therapy of mammalian diseases linked to mitochondrial dysfunctions. In summary, studies on the only partially known molecular interactions within the c-ring of the F1FO-complex may renew hope to counteract mammalian diseases.
Asunto(s)
Descubrimiento de Drogas , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , ATPasas de Translocación de Protón Mitocondriales/antagonistas & inhibidores , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Animales , Descubrimiento de Drogas/métodos , Humanos , Macrólidos/química , Macrólidos/farmacología , ATPasas de Translocación de Protón Mitocondriales/química , Modelos Moleculares , Terapia Molecular Dirigida/métodos , Compuestos Orgánicos de Estaño/química , Compuestos Orgánicos de Estaño/farmacología , Conformación Proteica/efectos de los fármacos , Quinolinas/química , Quinolinas/farmacologíaRESUMEN
Tributyltin (TBT), is a man-made pollutants, known to accumulate along the food chain, acting as an endocrine disruptor in marine organisms, with toxic and adverse effects in many tissues including vascular system. Based on the absence of specific studies of TBT effects on endothelial cells, we aimed to evaluate the toxicity of TBT on primary culture of porcine aortic endothelial cells (pAECs), pig being an excellent model to study human cardiovascular disease. pAECs were exposed for 24h to TBT (100, 250, 500, 750 and 1000nM) showing a dose dependent decrease in cell viability through both apoptosis and necrosis. Moreover the ability of TBT (100 and 500nM) to influence endothelial gene expression was investigated at 1, 7 and 15h of treatment. Gene expression of tight junction molecules, occludin (OCLN) and tight junction protein-1 (ZO-1) was reduced while monocyte adhesion and adhesion molecules ICAM-1 and VCAM-1 (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) levels increased significantly at 1h. IL-6 and estrogen receptors 1 and 2 (ESR-1 and ESR-2) mRNAs, after a transient decrease, reached the maximum levels after 15h of exposure. Finally, we demonstrated that TBT altered endothelial functionality greatly increasing monocyte adhesion. These findings indicate that TBT deeply alters endothelial profile, disrupting their structure and interfering with their ability to interact with molecules and other cells.
Asunto(s)
Células Endoteliales/efectos de los fármacos , Compuestos de Trialquiltina/toxicidad , Animales , Apoptosis/efectos de los fármacos , Adhesión Celular , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Relación Dosis-Respuesta a Droga , Células Endoteliales/metabolismo , Células Endoteliales/patología , Regulación de la Expresión Génica , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Necrosis , Porcinos , Proteínas de Uniones Estrechas/genética , Proteínas de Uniones Estrechas/metabolismo , Uniones Estrechas/efectos de los fármacos , Uniones Estrechas/metabolismo , Uniones Estrechas/patología , Factores de TiempoRESUMEN
A primary goal in antimicrobial drug design is to find molecules which inhibit key proteins in bacteria without affecting mammalian homologues. To this aim, structural differences between eukaryotic and prokaryotic enzyme proteins involved in life processes are widely exploited. The membrane-bound enzyme complex ATP synthase synthesizes the energy currency molecule of the cell. Due to its bioenergetic role, it represents "the enzyme of life" of all living beings. The enzyme complex has the unique bi-functional property of exploiting either the electrochemical transmembrane gradient to make ATP or, conversely, the free energy of ATP hydrolysis to build an electrochemical gradient across the membrane. The catalytic mechanism of ATP synthesis/hydrolysis, based on the coupling between the two rotary sectors FO and F1 is shared by eukaryotes and prokaryotes. However slight structural differences distinguish prokaryotic ATP synthases, embedded in cell membrane, from eukaryotic ones localized in the mitochondrial inner membrane. In spite of its fundamental task in living organisms, up to now the ATP synthase has been poorly exploited as target in antibacterial therapy, mainly due to harmful effects on patients. Recent advances shoulder the use of drugs targeting the ATP synthase to fight mycobacteria and treat human tuberculosis. Macrolide antibiotics and other antimicrobial drugs specifically bind to the c-ring of the membrane-embedded FO domain, thus blocking ion translocation through FO which is essential for both ATP synthesis and ATP hydrolysis. Our findings show that, once bound to the ATP synthase, probably through different binding sites on a common binding region on FO, the macrolide antibiotics oligomycin, venturicidin and bafilomycin behave as enzyme inhibitors. Interestingly, the c subunits of mitochondrial ATP synthase contain conserved cysteine residues which are absent in bacteria. We pointed out that when these crucial cysteine thiols are oxidized, the common drug binding site of the enzyme is somehow destabilized, thus weakening the enzyme-drug interactions and making the ATP synthase insensitive to drug inhibition. On these bases we hypothesize that the selective oxidation of these cysteine thiols can be exploited to desensitize the mitochondrial ATP synthase to drugs which target FO and maintain their inhibitory potency on bacterial ATP synthases. According to our hypothesis, this strategy could represent an intriguing tool to prevent adverse effects of antimicrobial drugs in mammals, thus enhancing the number of natural and synthetic compounds which can be used in therapy. To this aim studies should be addressed to the identification and formulation of compounds and/or treatments able to selectively oxidize the crucial cysteine thiols of c-subunits without affecting the overall functionality of the mitochondrial ATP synthase and other thiol containing proteins.
Asunto(s)
Antiinfecciosos/metabolismo , Diseño de Fármacos , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Modelos Biológicos , Compuestos de Sulfhidrilo/metabolismo , Antiinfecciosos/efectos adversos , Inhibidores Enzimáticos/metabolismo , Humanos , Oligomicinas , Oxidación-Reducción , VenturicidinasRESUMEN
Percutaneous core biopsy (CB) has been introduced to increase the ability of accurately diagnosing breast malignancies without the need of resorting to surgery. Compared to conventional automated 14 gauge needle core biopsy (NCB), vacuum-assisted needle core biopsy (VANCB) allows obtaining larger specimens and has recognized advantages particularly when the radiological pattern is represented by microcalcifications. Regardless of technical improvements, a small percentage of percutaneous CBs performed to detect breast lesions are still classified, according to European and UK guidelines, in the borderline B3 category, including a group of heterogeneous lesions with uncertain malignant potential. We aimed to assess the prevalence and positive predictive values (PPV) on surgical excision (SE) of B3 category (overall and by sub-categories) in a large series of non-palpable breast lesions assessed through VANCB, also comparison with published data on CB. Overall, 26,165 consecutive stereotactic VANCB were identified in 22 Italian centres: 3107 (11.9%) were classified as B3, of which 1644 (54.2%) proceeded to SE to establish a definitive histological diagnosis of breast pathology. Due to a high proportion of microcalcifications as main radiological pattern, the overall PPV was 21.2% (range 10.6%-27.3% for different B3 subtypes), somewhat lower than the average value (24.5%) from published studies (range 9.9%-35.1%). Our study, to date the largest series of B3 with definitive histological assessment on SE, suggests that B3 lesions should be referred for SE even if VANCB is more accurate than NCB in the diagnostic process of non-palpable, sonographically invisible breast lesions.
Asunto(s)
Biopsia con Aguja/métodos , Neoplasias de la Mama/patología , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/cirugía , Detección Precoz del Cáncer , Femenino , Humanos , Italia/epidemiología , Valor Predictivo de las Pruebas , Estudios RetrospectivosRESUMEN
Several tissues from different animals, including the rat kidney and the freshwater rainbow trout gills, show an ouabain-insensitive, furosemide-sensitive, Na(+)-stimulated ATPase activity, which has been associated with the active control of the cell volume. This Na-ATPase is Mg(2+) dependent and it is inhibited by vanadate, which can be taken as an indication that this enzyme is a P-type ATPase. The P-type ATPases are known to form a phosphorylated intermediate during their catalytic cycle, where the phosphate binds an aspartyl residue at the enzyme's substrate site. In the current study, we partially characterized the phosphorylated intermediate of the ouabain-insensitive Na-ATPase of rat kidney cortex homogenates and that of gill microsomes from freshwater rainbow trout. While the kidney cortex homogenates, under our assay conditions, show both Na- and Na,K-ATPase activities, the gill microsomes, when assayed at pH 5.2, only show Na-ATPase activity. Both preparations showed a Mg(2+)-dependent, Na(+)-stimulated phosphorylated intermediate, which is enhanced by furosemide. Incubation of the phosphorylated enzyme with 0.6 N hydroxylamine (NH(2)OH) showed that it is acid-stable and sensitive to hydroxylamine, either when phosphorylated in the presence or absence of furosemide. Addition of ADP to the incubation medium drives the reaction cycle of the enzyme backward, diminishing its phosphorylation. Na(+) seems to stimulate both the phosphorylation and the dephosphorylation of the enzyme, at least for the Na-ATPase from gill microsomes. In a E1-E2 reaction cycle of the Na-ATPase, furosemide seems to be blocking the transition step from Na.E1 approximately P to Na.E2-P.
Asunto(s)
Adenosina Trifosfatasas/metabolismo , Branquias/metabolismo , Corteza Renal/metabolismo , Oncorhynchus mykiss , Fosfoproteínas/metabolismo , Sodio/farmacología , Adenosina Trifosfato/metabolismo , Animales , Proteínas de Transporte de Catión/metabolismo , Furosemida/farmacología , Branquias/efectos de los fármacos , Branquias/enzimología , Corteza Renal/citología , Corteza Renal/efectos de los fármacos , Corteza Renal/enzimología , Masculino , Microsomas/efectos de los fármacos , Microsomas/enzimología , Microsomas/metabolismo , Ouabaína/farmacología , Fosforilación/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Vanadatos/farmacologíaRESUMEN
Bacteria and diatom strains from the Adriatic Sea were investigated, under standard and altered environmental conditions, for carbohydrate production and for the presence of specific biomarkers. Algae from P-depleted cultures showed an increase in extracellular carbohydrate production, a significantly lower chlorophyll a content and unchanged total lipid levels. However, the fatty acid composition of algal cultures was severely affected by low P levels, in that, total saturated and monounsaturated fatty acids increased and total polyunsaturated fatty acids decreased. Marine heterotrophic bacteria resulted enriched by 4 to 6 orders of magnitude in mucilage samples respect to surrounding seawater, unlike other groups of bacteria such as the non-halophylic heterotrophs. The major fatty acids detected in bacteria were 16:0 and 18:1n-7; the uneven fatty acids 17:0i, 17:0 and 17:1 also constituted an important component of various strains and, as a result, the total monounsaturated fraction represented the main component of total fatty acids. All the mucilage samples analysed shared the same general fatty acid composition features with a high amount of saturated components, especially 16:0; typical marine polyunsaturated fatty acids, such as 20:5n-3 and 22:6n-3, were found at very low levels. With regard to the sterol composition, the analysed algal species and bacteria showed that different compounds prevailed in the different species, and under P-deprivation sterol distribution resulted differently affected in the various algal species. In mucilage samples an overall prevalence of cholesterol was observed and, among 4alpha-methylsterols, constantly present, dinosterol prevailed in all samples. Vibrational IR spectroscopic analyses confirmed the main results obtained with the GC analysis: a higher unsaturation degree in nutrient replete diatom cultures than in P-depleted ones, a lower amount of P-containing compounds in the latter, bacterial lipid profiles with a high amount of free carboxylic acids and/or ketones and a low unsaturation degree and, finally, mucilage samples with a very low unsaturation degree. All these results allowed some speculations on the involvement of the various microbial and phytoplankton components in mucilage genesis.
Asunto(s)
Bacterias/química , Diatomeas/química , Biología Marina/estadística & datos numéricos , Fitoplancton/química , Biomarcadores/metabolismo , Carbohidratos/análisis , Células Cultivadas , Clorofila/análisis , Clorofila A , Cromatografía de Gases , Lípidos/análisis , Mar Mediterráneo , Agua de Mar/química , Especificidad de la Especie , Espectrofotometría Infrarroja , Esteroles/análisisRESUMEN
The effect of the administration of commercial diets supplemented with 9 mg kg(-1) 3,5,3'-triiodo-l-thyronine (T(3)) or 10% (w/w) NaCl was evaluated on the ouabain-insensitive Na+-ATPase activity in rainbow trout gill microsomes. The trial, carried out following the seasonal trend from March to mid-May, included a treatment phase in freshwater and a subsequent transfer to brackish water (22 per thousand salinity) where trout were not treated. pH dependence, apparent Km values for Mg(2+) and Na+, and Hill coefficients evaluated throughout the trial for Na+-ATPase were generally not affected by the treatments and habitat change. In comparison with the control group, in both treated groups, Na+-ATPase activity was lower during the freshwater phase and higher after brackish-water transfer. As compared with untreated trout, gill (Na++K+)-ATPase activity during the freshwater phase was stimulated by NaCl treatment and also by T(3) treatment after transfer to brackish water. The results indicate that NaCl and T(3) administration act differently on the two ATPase activities involved in Na+ regulation and suggest a prevalent role of Na+-ATPase activity in hypoosmotic conditions.
Asunto(s)
Adenosina Trifosfatasas/metabolismo , Proteínas de Transporte de Catión , Branquias/fisiología , Oncorhynchus mykiss/fisiología , Animales , Concentración de Iones de Hidrógeno , Microsomas/fisiología , Ósmosis , Cloruro de Sodio/farmacología , Tironinas/farmacología , Equilibrio HidroelectrolíticoRESUMEN
AIMS AND BACKGROUND: The authors report the case of a 23-year-old woman affected by intra-abdominal desmoplastic small round cell tumor (DSRCT) who obtained a complete response to multiagent chemotherapy. DSRCT is a rare, highly aggressive neoplasm generally arising in young people and seldom in females (about 20 cases described in the literature). METHODS: The patient underwent surgical resection of a large 15 x 15 cm mass located in the right lower abdominal quadrant, but after only 2 months later, two liver metastasis were noted. Thus, she was subjected to an aggressive antineoplastic treatment consisting of three groups of alternating non-cross resistant multiagent regimens administered every 21 days (cis-platin-etoposide-adriamycin-bleomicin; gemcitabine-ifosfamide-dacarbazine; methotrexate-5-fluorouracil-folinic acid) for a total of 9 administrations. RESULTS: After one cycle of treatment including the administration of all the three alternated schemes of chemotherapy, a complete disappearance of liver disease was noted. The treatment was relatively well-tolerated and the toxicity was acceptable. At present, after 15 months from diagnosis and 12 months after starting chemotherapy, the patient is disease-free and in good health. CONCLUSIONS: Even though this study regards only a single patient, it is noteworthy because of the rarity of this neoplasm and because of the infrequent complete responses reported in the literature. The efficacy and manageability of the treatment, suggests that both the timing and schedule used could constitute an important therapeutical option for this aggressive and poorly chemo-responsive tumor.
Asunto(s)
Neoplasias Abdominales/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Células Pequeñas/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Abdominales/patología , Neoplasias Abdominales/cirugía , Adulto , Carcinoma de Células Pequeñas/secundario , Carcinoma de Células Pequeñas/cirugía , Quimioterapia Adyuvante , Femenino , Humanos , Neoplasias Hepáticas/secundarioRESUMEN
With the aim of comparing the effects of oral T3 and NaCl administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3'-triiodo-L-thyronine (T3) (T) or 10% (w/w) NaCl (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na(+)+K(+))-ATPase activity and its dependence on ATP, Na(+) and pH, number of gill chloride cells (CC), serum T3 level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T3 level, had unchanged gill (Na(+)+K(+))-ATPase activity and increased CC number, whereas N trout showed higher gill (Na(+)+K(+))-ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T>N>C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na(+). A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T3 administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na(+)+K(+))-ATPase activity unaltered till the transfer to a hyperosmotic environment.
RESUMEN
PURPOSE: To improve response and toxicity in treatment of non-Hodgkin's lymphomas (NHLs), a prospective single-arm trial was initiated using cyclophosphamide, epirubicin, vincristine, prednisone, and bleomycin (CEOP-B) alternated with etoposide (VP-16), ifosfamide, mitoxantrone, and bleomycin (VIMB). PATIENTS AND METHODS: From December 1988 to April 1992, 60 consecutive previously untreated patients with intermediate- or high-grade NHL were admitted to the study and were assessable. Patient characteristics were as follows: 32% greater than 60 years of age, 63% with stage III to IV disease, 42% with a performance status (PS) of 2 or 3, 23% with high lactate dehydrogenase (LDH) levels, and 22% with two or more extranodal disease sites. Stage I and II patients received three cycles of CEOP-B/VIMB plus radiotherapy (RT) to involved fields; stage III and IV patients received four cycles of chemotherapy alone. RESULTS: The complete remission (CR) rate was 77%; actuarial 48-month overall survival (OS) and time to treatment failure (TTF) rates were 70% and 59%, respectively. With univariate analysis, CR, OS, and TTF rates were significantly influenced by serum LDH levels (P = .0485, P = .0017, and P = .0064, respectively) and performance status (P = .0005, P < .00005, and P = .0001, respectively). The actuarial 48-month disease-free survival (DFS) rate was 83% and was negatively influenced only by high-grade histology (P < .004). Toxicity was mild. A lower epirubicin dose-intensity (DI) was found in patients older than 60 years of age, with a borderline P value. Patients were divided into four groups according to the International Prognostic Factor Project; low-risk and low-intermediate-risk groups had similar OS and TTF rates; when considered together, they showed superior, but not statistically significant, OS and TTF rates as compared with the high-intermediate-risk group, which in turn had significantly superior OS and TTF rates when compared with the high-risk group. CONCLUSION: CEOP-B/VIMB compares favorably with third-generation regimens and results in lower toxicity.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Linfoma no Hodgkin/tratamiento farmacológico , Análisis Actuarial , Adulto , Anciano , Análisis de Varianza , Bleomicina/administración & dosificación , Distribución de Chi-Cuadrado , Ciclofosfamida/administración & dosificación , Supervivencia sin Enfermedad , Esquema de Medicación , Epirrubicina/administración & dosificación , Etopósido/administración & dosificación , Femenino , Humanos , Ifosfamida/administración & dosificación , Estado de Ejecución de Karnofsky , L-Lactato Deshidrogenasa/sangre , Linfoma no Hodgkin/mortalidad , Masculino , Persona de Mediana Edad , Mitoxantrona/administración & dosificación , Proyectos Piloto , Prednisona/administración & dosificación , Pronóstico , Estudios Prospectivos , Inducción de Remisión , Tasa de Supervivencia , Insuficiencia del Tratamiento , Vincristina/administración & dosificaciónRESUMEN
AIMS: A comparative analysis was performed to verify a possible correlation between mammographic features and morphobiologic characteristics of the tumor in a series of 176 invasive primary breast cancer patients. METHODS: Breast cancers were grouped according to mammographic features as follows: tumor mass with spiculated borders; tumor mass with well-circumscribed borders; tumor with density alteration of parenchyma with no clear borders; a cluster of microcalcifications as the only sign of tumor presence; tumor without mammographic abnormality. The tumor tissue biologic characteristics investigated were: hormone receptor content, tumor proliferative activity, DNA content and cytohistologic tumor-grade differentiation. RESULTS: Spiculated tumors showed a significantly higher percentage of estrogen-receptor-positive cases with respect to circumscribed tumors, independently of the patient's menopausal status. Tumors with only microcalcifications were all from premenopausal patients and showed a significantly higher percentage of progesterone-receptor-positive cases (83%). Tumor proliferative activity did not significantly differ in the 5 mammographic breast cancer groups; aneuploidy was less frequent in tumors with spiculated borders than in mammographic types (39% vs 57%; p = 0.05); percentages of G1-G2-G3 tumors did not differ significantly among the mammographic groups considered. CONCLUSIONS: Certain relationships between mammographic features and biologic characteristics could be of potential clinical interest and stimulate more detailed studies on this issue.
Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Mamografía , Adulto , Neoplasias de la Mama/química , División Celular , ADN de Neoplasias/análisis , Femenino , Citometría de Flujo , Humanos , Persona de Mediana Edad , Invasividad Neoplásica , Receptores de Estrógenos/análisis , Receptores de Progesterona/análisis , Estudios RetrospectivosRESUMEN
To investigate the relationships between the mammographic aspects (according to Broberg), proliferative activity and hormone receptor status, we studied 165 patients subjected to radical mastectomy for operable breast cancer. The highest percentage of estrogen receptor-positive cases was observed in mammograph class I (p < 0.02) while classes III and V were highest in progesterone receptor-positive cases. Proliferative activity (111 cases) was significantly lower in class I and IV with respect to all other classes (p < 0.03 and p < 0.01, respectively). This study suggests that certain mammographic signs can be related to the biological characteristics of breast cancer.
Asunto(s)
Neoplasias de la Mama/patología , Carcinoma Intraductal no Infiltrante/patología , Neoplasias Hormono-Dependientes/patología , Receptores de Estrógenos/análisis , Receptores de Progesterona/análisis , Neoplasias de la Mama/clasificación , Neoplasias de la Mama/cirugía , Carcinoma Intraductal no Infiltrante/clasificación , Carcinoma Intraductal no Infiltrante/cirugía , Ciclo Celular , División Celular/fisiología , Femenino , Humanos , Mamografía , Estadificación de Neoplasias , Neoplasias Hormono-Dependientes/clasificación , Neoplasias Hormono-Dependientes/cirugía , Timidina/metabolismo , TritioRESUMEN
The response to cold of gill and kidney membrane lipid composition and microsomal (Na(+)+K(+))-ATPase, Na(+)-ATPase and Mg(2+)-ATPase activities in reared sea bass (Dicentrarchus labrax L.) was investigated. Fish acclimation was carried out according to the seasonal cycle from August to March. No cold-promoted increase in fatty acid unsaturation was shown in gill and kidney polar lipids and in total lipids of mitochondria and microsomes. In both tissues the (Na(+)+K(+))-ATPase exhibited positive compensation for cold acclimation whereas the Na(+)-ATPase displayed negative compensation. The Mg(2+)-ATPase showed no compensation in the gills and positive compensation in the kidneys. During cold acclimation the break in the Arrhenius plot of the (Na(+)+K(+))-ATPase decreased, whereas breaks of both the Na(+)-ATPase and the Mg(2+)-ATPase activities remained unchanged. The results indicate that the sea bass does not adopt membrane unsaturation as a cold-facing strategy. The cold-promoted enhancement of (Na(+)+K(+))-ATPase activity in osmoregulatory tissues may be advantageous to maintain efficient osmoregulation under thermodynamically unfavourable conditions.
RESUMEN
1. The involvement of gill (Na+ +K+)-ATPase in salmonid adaptation to salt water (SW) is discussed. 2. Gill (Na+ +K+)-ATPase increase during SW adaptation is mainly related to the increased number and complexity of chloride cells deputed to salt extrusion. 3. The temporal relationships between serum peaks of thyroid hormones, cortisol, growth hormone, prolactin and gill (Na+ +K+)-ATPase rise during salmonid smoltification, suggest a hormonal involvement in the enzyme stimulation and thus in the acquirement of SW tolerance. 4. Literature on gill (Na+ +K+)-ATPase response to hormonal treatment is reviewed. The effects produced on gill (Na+ +K+)-ATPase and chloride cells by exogenous hormones point out a complex inter-relationship between the hormones considered. The mechanisms involved in hormonal regulation of the enzyme remain a matter of debate.
Asunto(s)
Branquias/enzimología , Salmonidae/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Adaptación Fisiológica , Animales , Agua de MarRESUMEN
The response to cold of liver and heart membrane lipid composition and mitochondrial respiration in reared sea bass (Dicentrarchus labrax L.) was investigated. Fish acclimation was followed during the natural seasonal cycle from August to March. The data on the fatty acid composition of liver and heart polar lipids and on total lipids of liver mitochondria and microsomes did not indicate any increase in unsaturation in response to cold. The enzyme complexes of the liver and heart mitochondrial respiratory chain showed a repeated negative compensation for cold acclimation. The constancy of the break in the Arrhenius plot of liver cytochrome oxidase (EC 1.9.3.1) was consistent with the lack of homeoviscous adaptation of membrane lipids. A thermoadaptive strategy based on the reduction of sea bass metabolic activity is suggested.
Asunto(s)
Aclimatación/fisiología , Lubina/metabolismo , Lípidos/análisis , Mitocondrias/fisiología , Consumo de Oxígeno/fisiología , Temperatura , Animales , Microsomas/metabolismoRESUMEN
To verify the relationship of mammographic (Mx) patterns of breast cancer to hormone receptor content (ER, PgR) we studied 129 women (59% in postmenopause; average age 55) in the last 3 years. All women had operable breast cancer and were submitted to mammography before surgery. The tumors were classified, according to Mx characteristics, in 5 classes (Broberg, 1983). ER and PgR contents (cut-off for positivity: 10 fmol/mg prot cyt) were analyzed in all patients by means of DCC method. The percentage of ER+ cases was significantly higher in class I than in all other Mx classes (85% vs 57%; p = 0.02), whereas it was lowest in class IV (51% vs 70%; p = 0.03). The percentage of PgR+ cases was significantly different only in class I with respect to class IV (70% vs 41%; p = 0.002). As for ER and PgR mean tumor content, no statistically significant difference was observed between the 5 classes. When the 2 receptors were simultaneously considered the percentage of ER+ PgR+ cases was higher in class I than in all the extant classes (p = 0.01), and the percentage of ER- PgR- was higher in class IV than in the extant ones (p = 0.02). In selected subgroups of patients, Mx classification of breast cancer can help the physician predict the hormone receptor tumor status with sufficient reliability.
Asunto(s)
Neoplasias de la Mama/análisis , Mama/análisis , Carcinoma/análisis , Mamografía , Receptores de Estrógenos/análisis , Receptores de Progesterona/análisis , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/cirugía , Carcinoma/diagnóstico por imagen , Carcinoma/cirugía , Femenino , Humanos , Persona de Mediana Edad , PronósticoRESUMEN
1. Gilthead gill 10(-3) M ouabain-inhibited (Na+ + K+)-ATPase and 10(-2) M ouabain-insensitive Na+-ATPase require the optimal conditions of pH 7.0, 160 mM Na+, 20 mM K+, 5 mM MgATP and pH 4.8-5.2, 75 mM Na+, 2.5 mM Mg2+, 1.0 mM ATP, respectively. 2. The main distinctive features between the two activities are confirmed to be optimal pH, the ouabain-sensitivity and the monovalent cation requirement, Na+ plus another cationic species (K+, Rb+, Cs+, NH4+) in the (Na+ + K+)-ATPase and only one species (Na+, K+, Li+, Rb+, Cs+, NH4+ or choline+) in the Na+-ATPase. 3. The aspecific Na+-ATPase activation by monovalent cations, as well as by nucleotide triphosphates, opposed to the (Na+ + K+)-ATPase specificity for ATP and Na+, relates gilthead gill ATPases to lower organism ATPases and differentiates them from mammalian ones. 4. The discrimination between the two activities by the sensitivity to ethacrynic acid, vanadate, furosemide and Ca2+ only partially agrees with the literature. 5. Present findings are viewed on the basis of the ATPase's presumptive physiological role(s) and mutual relationship.
Asunto(s)
Adenosina Trifosfatasas/metabolismo , ATPasa de Ca(2+) y Mg(2+)/metabolismo , Proteínas de Transporte de Catión , Branquias/enzimología , Perciformes/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Amilorida/farmacología , Animales , Calcio/farmacología , Cationes Monovalentes/farmacología , Ácido Etacrínico/farmacología , Furosemida/farmacología , Calor , Concentración de Iones de Hidrógeno , Magnesio/farmacología , Microsomas/enzimología , Nucleótidos/farmacología , Ouabaína/farmacología , Vanadatos/farmacologíaRESUMEN
1. Sea bass kidney microsomal preparations contain two Mg2+ dependent ATPase activities: the ouabain-sensitive (Na+ + K+)-ATPase and an ouabain-insensitive Na+-ATPase, requiring different assay conditions. The (Na+ + K+)-ATPase under the optimal conditions of pH 7.0, 100 mM Na+, 25 mM K+, 10 mM Mg2+, 5 mM ATP exhibits an average specific activity (S.A.) of 59 mumol Pi/mg protein per hr whereas the Na+-ATPase under the conditions of pH 6.0, 40 mM Na+, 1.5 mM MgATP, 1 mM ouabain has a maximal S.A. of 13.9 mumol Pi/mg protein per hr. 2. The (Na+ + K+)-ATPase is specifically inhibited by ouabain and vanadate; the Na+-ATPase specifically by ethacrynic acid and preferentially by frusemide; both activities are similarly inhibited by Ca2+. 3. The (Na+ + K+)-ATPase is specific for ATP and Na+, whereas the Na+-ATPase hydrolyzes other substrates in the efficiency order ATP greater than GTP greater than CTP greater than UTP and can be activated also by K+, NH4+ or Li+. 4. Minor differences between the two activities lie in the affinity for Na+, Mg2+, ATP and in the thermosensitivity. 5. The comparison between the two activities and with what has been reported in the literature only partly agree with our findings. It tentatively suggests that on the one hand two separate enzymes exist which are related to Na+ transport and, on the other, a distinct modulation in vivo in different tissues.
Asunto(s)
Adenosina Trifosfatasas/metabolismo , Lubina/metabolismo , ATPasa de Ca(2+) y Mg(2+)/metabolismo , Proteínas de Transporte de Catión , Riñón/enzimología , Perciformes/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Animales , Cationes Monovalentes , Cinética , Microsomas/enzimología , TermodinámicaRESUMEN
The Mg2+-dependent ouabain insensitive-ATPase activity present in gill microsomal preparations from Dicentrarchus labrax is stimulated not only by Na+ but also by K=, NH4+ or Li+. These cations at 50-100 mM concentrations are similarly efficient to Na+ in stimulating the enzyme activity with similar Km values. Whatever cation stimulates the activity, the enzyme is poorly sensitive to ouabain and 100% inhibited by 1.5-2.5 mM ethacrynic acid. All activity vs cation concentration curves show a biphasic profile with activation following the Michaelis-Menten kinetics (Hill coefficient approximately 2). The absence of additivity when the enzyme is activated by binary mixtures of cations, each of which may act as competitive inhibitor of the other confirms the involvement of the same binding site for the monovalent cations.