[Lipid lowering treatment of severe hypertriglyceridemia with acute pancreatitis caused by everolimus in a patient with a neuroendocrine tumor]. / Tratamiento hipolipemiante de la pancreatitis aguda secundaria a hipertrigliceridemia severa por everolimus en un paciente con tumor neuroendocrino.

Everolimus is an mTOR inhibitor, approved as a treatment for cancer and as an immunosuppressant agent in solid organ transplantation; it frequently produces toxic metabolic effects, particularly of the most severe kind. Its use can cause hyperglycemia, hypercholesterolemia and hypertriglyceridemia; thus, metabolic values should be monitored regularly to prevent these adverse events. We present the case of a woman with an intestinal neuroendocrine tumor who developed two episodes of acute pancreatitis, secondary to severe hypertriglyceridemia caused by everolimus. After treatment with fibrates and omega-3, triglyceride levels returned to baseline, without developing new metabolic or digestive complications. Targeted levels of triglyceride for cancer patients treated with everolimus, should be below 500 or 300 mg/dL, depending on whether life expectancy is less or longer than one year, respectively.

Tratamiento hipolipemiante de la pancreatitis aguda secundaria a hipertrigliceridemia severa por everolimus en un paciente con tumor neuroendocrino / Lipid lowering treatment of severe hypertriglyceridemia with acute pancreatitis caused by everolimus in a patient with a neuroendocrine tumor

Everolimus es un inhibidor de mTOR, empleado en oncología y como inmunosupresor en el trasplante de órgano sólido. Sus efectos adversos a nivel metabólico son muy frecuentes, especialmente los más severos. Puede ocasionar hiperglucemia, hipercolesterolemia e hipertrigliceridemia, por lo que la monitorización de los parámetros metabólicos en las sucesivas visitas es vital para detectar e iniciar tratamientos que puedan prevenir las complicaciones. Se presenta el caso de una mujer con diagnóstico de tumor neuroendocrino intestinal que desarrolló dos pancreatitis agudas secundarias a hipertrigliceridemia severa por everolimus. Tras inicio de tratamiento con fibratos y omega-3, se normalizó la cifra de triglicéridos sin presentar nuevas complicaciones metabólicas ni digestivas secundarias al fármaco. La recomendación en pacientes con cáncer en tratamiento activo con everolimus es mantener los triglicéridos por debajo de 500 o 300 mg/dL, dependiendo de si la esperanza de vida es inferior o superior a un año, respectivamente

Everolimus is an mTOR inhibitor, approved as a treatment for cancer and as an immunosuppressant agent in solid organ transplantation; it frequently produces toxic metabolic effects, particularly of the most severe kind. Its use can cause hyperglycemia, hypercholesterolemia and hypertriglyceridemia; thus, metabolic values should be monitored regularly to prevent these adverse events. We present the case of a woman with an intestinal neuroendocrine tumor who developed two episodes of acute pancreatitis, secondary to severe hypertriglyceridemia caused by everolimus. After treatment with fibrates and omega-3, triglyceride levels returned to baseline, without developing new metabolic or digestive complications. Targeted levels of triglyceride for cancer patients treated with everolimus, should be below 500 or 300 mg/dL, depending on whether life expectancy is less or longer than one year, respectively

Identification and translational validation of novel mammaglobin-A CD8 T cell epitopes.

Mammaglobin-A (MAM-A) is a secretory protein that is overexpressed in 80 % of human breast cancers. Its near-universal expression in breast cancer as well as its exquisite tissue specificity makes it an attractive target for a breast cancer prevention vaccine, and we recently initiated a phase 1 clinical trial of a MAM-A DNA vaccine. Previously, we have identified multiple MAM-A CD8 T cell epitopes using a reverse immunology candidate epitope approach based on predicted binding, but to date no attempt has been made to identify epitopes using an unbiased approach. In this study, we used human T cells primed in vitro with autologous dendritic cells expressing MAM-A to systematically identify MAM-A CD8 T cell epitopes. Using this unbiased approach, we identified three novel HLA-A2-restricted MAM-A epitopes. CD8 T cells specific for these epitopes are able to recognize and lyse human breast cancer cells in a MAM-A-specific, HLA-A2-dependent fashion. HLA-A2(+)/MAM-A(+) breast cancer patients have an increased prevalence of CD8 T cells specific for these novel MAM-A epitopes, and vaccination with a MAM-A DNA vaccine significantly increases the number of these CD8 T cells. The identification and translational validation of novel MAM-A epitopes has important implications for the ongoing clinical development of vaccine strategies targeting MAM-A. The novel MAM-A epitopes represent attractive targets for epitope-based vaccination strategies, and can also be used to monitor immune responses. Taken together these studies provide additional support for MAM-A as an important therapeutic target for the prevention and treatment of breast cancer.

[Intra-dialysis parenteral nutrition in chronic renal patients: consensus SEN-SENPE]. / Nutrición parenteral intradiálisis en el enfermo renal crónico: consenso SEN-SENPE.

Given the high prevalence of the hyponutrition state among haemodialysis patients and knowing that this implies an increase in the rates of infection, hospitalisation and hospital stay, which translates into an increase in global morbid-mortality, the Spanish Society of Nephrology (SEN) and the Spanish Society of Parenteral and Enteral Nutrition (SENPE) have reached a consensus on the indications, contraindications, and limitations of Intra-Dialysis Parenteral Nutrition (IDPN.) This consensus considers IDPN as a valid alternative to other types of nutritional support when these show their lack of efficacy. The bases are set regarding the timing of nutritional intervention with IDPN, its ideal composition, the time of administration, its controls, follow-up schedules, and the time at which the nutritional support has to be discontinued.

Induction of multiepitopic and long-lasting immune responses against tumour antigens by immunization with peptides, DNA and recombinant adenoviruses expressing minigenes.

The development of immunization strategies to induce strong and multiepitopic T-cell responses against tumour antigens is needed for anti-tumour immunotherapy. However, a common finding after immunization with complex antigens is the preferential induction of immune responses against immunodominant epitopes. In this study, with the aim of inducing multiepitopic responses against several common tumour antigens, we have designed a minigene construct encoding four human leucocyte antigen (HLA)-A2-restricted epitopes belonging to tumour antigens CEA (CEA-691 and CEA-571), MAGE2 (MAGE2-157) and MAGE3 (MAGE3-112), as well as the universal PADRE epitope recognized by T helper lymphocytes. To optimize the activation of immune responses against these epitopes, we have used different antigen formats (short peptides encompassing individual epitopes and DNA plasmids or adenoviral constructs expressing the minigene) in single or combined immunization schedules. A single immunization with either DNA plasmid or recombinant adenovirus induced a monospecific immune response against the immunodominant epitope CEA-571, whereas immunization with the peptide pool induced responses against all epitopes. Combination of peptide priming followed by a boost with the plasmid and the recombinant adenovirus expressing the minigene induced stronger, multi-specific and long-lasting immune responses, overcoming the immunodominance imposed by the main T-cell epitope. Moreover, these combined immunization strategies were able to induce responses that were able to recognize Mel624 HLA-A2+ tumour cells expressing MAGE2. These results suggest that heterologous immunization strategies combining peptides and DNA or recombinant adenoviruses can be useful to broaden the specificity and enhance the efficacy of subunit vaccines.

Síndrome metabólico en pacientes en hemodiálisis / Metabolic syndrome in patients on hemodialysis

La morbimortalidad por problemas cardiovasculares en pacientes en programas de hemodiálisis periódica es mayor que en la población general, coincidiendo a la vez más de un factor de riesgo, entre los que destacan la hipertensión arterial, dislipidemia o alteraciones de los hidratos de carbono, entre otros. Siguiendo los criterios de la ATP III (Adult Treatment Panel), se han estudiado los pacientes que se engloban en el síndrome metabólico valorando los factores de riesgo más frecuentes que lo constituyen. La obesidad, tanto medida por el índice de masa corporal (IMC) como por la circunferencia de cintura, es el factor que se ha observado con mayor incidencia. La resistencia a la insulina, medida por el test de HOMA, se ha incluido igualmente en el estudio por sus implicaciones en esta patología

Cardiovascular disease morbidity-mortality is higher in patients on periodic dialysis than in the general population, there being more than one risk factor at the same time. Among these, hypertension, dyslipidemia and carbohydrate alterations stand out. Following the ATP III (Adult Treatment Panel) criteria, patients included under the metabolic syndrome have been studied, evaluating the most important risk factors that make it up. Obesity, measured with body mass index (BMI) or with the waist circumference, is the factor observed with the greatest incidence. In addition, insulin resistance measured by the HOMA test has been included due to its relevant implications in this disease

[The immunotherapy potential of agonistic anti-CD137 (4-1BB) monoclonal antibodies for malignancies and chronic viral diseases]. / El potencial de la inmunomodulación con anticuerpos monoclonales anti-CD137 (4-1BB) para terapia de enfermedades malignas e infecciones virales crónicas.

Pharmacological intervention on the immune system to achieve more intense lymphocyte responses has potential application in tumour immunology and in the treatment of chronic viral diseases. Immunostimulating monoclonal antibodies are defined as a new family of drugs that augment cellular immune responses. They interact as artificial ligands with functional proteins of the immune system, either activating or inhibiting their functions. There are humanized monoclonal antibodies directed to the inhibitory receptor CD152 (CTLA-4) that are being tested in clinical trials with evidence of antitumoural activity. As a drawback, anti-CTLA-4 monoclonal antibodies induce severe autoimmunity reactions in a fraction of the patients. Anti-CD137 monoclonal antibodies have the ability to induce potent immune responses mainly mediated by cytotoxic lymphocytes with the result of frequent complete tumour eradications in mice. Comparative studies in experimental models indicate that the antitumour activity of anti-CD137 monoclonal antibodies is superior to that of anti-CD152. CD137 (4-1BB) is a leukocyte differentiation antigen selectively expressed on the surface of activated T and NK lymphocytes, as well as on dendritic cells. Monoclonal antibodies acting as artificial stimulatory ligands of this receptor (anti-CD137 agonist antibodies) enhance cellular antitumoural and antiviral immunity in a variety of mouse models. Paradoxically, anti-CD137 monoclonal antibodies are therapeutic or preventive in the course of model autoimmune diseases in mice. In light of these experimental results, a number of research groups have humanized antibodies against human CD137 and early clinical trials are about to start.

El potencial de la inmunomodulación con anticuerpos monoclonales anti-CD137 (4-1BB) para terapia de enfermedades malignas e infecciones virales crónicas / The immunotherapy potential of agonistic anti-CD137 (4-1BB) monoclonal antibodies for malignancies and chronic viral diseases

La manipulación farmacológica del sistema inmunitario para conseguir respuestas linfocitarias de mayor intensidad tiene aplicación potencial en inmunoterapia tumoral y en el tratamiento de enfermedades virales crónicas. Los anticuerpos monoclonales inmunoestimuladores se definen como una familia de fármacos que aumentan la respuesta inmunitaria al interaccionar como ligandos artificiales con proteínas funcionales del sistema inmunitario, activando o inhibiendo su función. Hay anticuerpos monoclonales humanizados dirigidos frente al receptor inhibidor linfocitario CD152 (CTLA-4) que se están probando en ensayos clínicos con evidencia de actividad antitumoral, aunque con la contrapartida de producir reacciones autoinmunitarias severas. Los anticuerpos anti-CD137 tienen la capacidad de inducir potentes respuestas inmunitarias, mediadas principalmente por linfocitos T citotóxicos, con el resultado de erradicar tumores transplantables de ratón de forma comparativamente superior a los anticuerpos frente a CD152. CD137 (4-1BB) es un antígeno de diferenciación expresado selectivamente en la superficie de linfocitos T y NK activados y sobre células dendríticas. Los anticuerpos monoclonales que actúan como ligandos artificiales estimuladores de este receptor (anticuerpos monoclonales agonistas anti-CD137) potencian la inmunidad celular antitumoral y antiviral en modelos experimentales murinos. Paradójicamente, estos mismos anticuerpos previenen o mejoran el curso de enfermedades autoinmunitarias establecidas en ratones como modelo. A la luz de estos datos experimentales, varios grupos de investigación han procedido a la humanización de anticuerpos dirigidos frente a CD137 humano y se plantea la inminente realización de los primeros ensayos clínicos

Pharmacological intervention on the immune system to achieve more intense lymphocyte responses has potential application in tumour immunology and in the treatment of chronic viral diseases. Immunostimulating monoclonal antibodies are defined as a new family of drugs that augment cellular immune responses. They interact as artificial ligands with functional proteins of the immune system, either activating or inhibiting their functions. There are humanized monoclonal antibodies directed to the inhibitory receptor CD152 (CTLA-4) that are being tested in clinical trials with evidence of antitumoural activity. As a drawback, anti-CTLA-4 monoclonal antibodies induce severe autoimmunity reactions in a fraction of the patients. Anti-CD137 monoclonal antibodies have the ability to induce potent immune responses mainly mediated by cytotoxic lymphocytes with the result of frequent complete tumour eradications in mice. Comparative studies in experimental models indicate that the antitumour activity of anti-CD137 monoclonal antibodies is superior to that of anti-CD152. CD137 (4-1BB) is a leukocyte differentiation antigen selectively expressed on the surface of activated T and NK lymphocytes, as well as on dendritic cells. Monoclonal antibodies acting as artificial stimulatory ligands of this receptor (anti-CD137 agonist antibodies) enhance cellular antitumoural and antiviral immunity in a variety of mouse models. Paradoxically, anti-CD137 monoclonal antibodies are therapeutic or preventive in the course of model autoimmune diseases in mice. In light of these experimental results, a number of research groups have humanized antibodies against human CD137 and early clinical trials are about to start

Critical appraisal of the current status of dendritic cell based therapy

Una serie de circunstancias históricas han otorgado a las células dendríticas un lugar importante en la inmunoterapia antitumoral. El descubrimiento de su papel fundamental en la presentación antigénica ha propiciado su uso como adyuvantes en protocolos de vacunación en modelos tumorales de ratón. En estos modelos se llegaron a obtener remisiones tumorales. A finales de los años 90 la coincidencia de (i) estos prometedores resultados preclínicos, (ii) la disponibilidad en hospitales de áreas de terapiacelular (desarrolladas sobre todo para transplantes de médula ósea y (iii) protocolos de cultivo sencillos para diferenciar células dendríticas a partir de monocitos o precursores mieloides han impulsado la realización de múltiples ensayos clínicos. Los primeros datos clínicos no cumplieron las expectativas, pero se están extrayendo conclusiones sobre la actividad biológica e incluso se han obtenido algunos casos de respuestas clínicas en pacientes con cánceres avanzados. En cualquier caso, algunos de los ensayos que mejores resultados estaban obteniendo se encuentran bajo sospecha de fraude científico y otros buenos resultados obtenidos en los grupos piloto no se han reproducido cuando se han utilizado los mismos protocolos en grupos más amplios de pacientes.La situación actual del campo puede ser vista como una botella medio llena o medio vacía. En cualquier caso, se necesita mejorarla potencia terapéutica a nivel preclínico incluso con el riesgo de efectos adversos (AU)

A set of historical circumstances has centred the field of cancer immunotherapy on dendritic cells (DC). The discovery of their central role in antigen presentation for immunization gave rise to their use as adjuvants for cancer vaccination in transplantable tumour models in mice. Tumour rejections of experimental transplantable tumour models were achieved. During the late 90s concurrence of (i) this encouraging preclinical data, (ii) the availability of hospital cell therapy facilities that have been mainly set up for bone marrow transplantation and (iii) simple culture means to differentiate DC from monocytes or myeloid precursors spurred many clinical trials worldwide. Early clinical experience has not met the great expectations raised, but many lessons are being learned in terms of biological activity and cases of clinical response in advanced cases are routinely reported. However, some of the trials that reported the most encouraging clinical responses have confronted controversy due to scientific misconduct orto accumulation of successful cases in the pilot groups of patients that were not so reproducible when more patients were studied under the same protocols. The current status of the field could be seen as a half empty or a half full bottle. In either case, improvements are needed from the lab bench to increase therapeutic potency, even at the risk of side effects (AU)

Critical appraisal of the current status of dendritic cell based therapy

Una serie de circunstancias históricas han otorgado a las célulasdendríticas un lugar importante en la inmunoterapia antitumoral.El descubrimiento de su papel fundamental en la presentaciónantigénica ha propiciado su uso como adyuvantes en protocolosde vacunación en modelos tumorales de ratón. En estosmodelos se llegaron a obtener remisiones tumorales. A finales delos años 90 la coincidencia de (i) estos prometedores resultadospreclínicos, (ii) la disponibilidad en hospitales de áreas de terapiacelular (desarrolladas sobre todo para transplantes de médulaósea y (iii) protocolos de cultivo sencillos para diferenciar célulasdendríticas a partir de monocitos o precursores mieloides hanimpulsado la realización de múltiples ensayos clínicos. Los primerosdatos clínicos no cumplieron las expectativas, pero se estánextrayendo conclusiones sobre la actividad biológica e incluso sehan obtenido algunos casos de respuestas clínicas en pacientescon cánceres avanzados. En cualquier caso, algunos de los ensayosque mejores resultados estaban obteniendo se encuentran bajosospecha de fraude científico y otros buenos resultados obtenidosen los grupos piloto no se han reproducido cuando se hanutilizado los mismos protocolos en grupos más amplios de pacientes.La situación actual del campo puede ser vista como una botellamedio llena o medio vacía. En cualquier caso, se necesita mejorarla potencia terapéutica a nivel preclínico incluso con el riesgode efectos adversos

A set of historical circumstances has centred the field of cancerimmunotherapy on dendritic cells (DC). The discovery of theircentral role in antigen presentation for immunization gave rise totheir use as adjuvants for cancer vaccination in transplantabletumour models in mice. Tumour rejections of experimental transplantabletumour models were achieved. During the late 90s concurrenceof (i) this encouraging preclinical data, (ii) the availabilityof hospital cell therapy facilities that have been mainly set upfor bone marrow transplantation and (iii) simple culture meansto differentiate DC from monocytes or myeloid precursors spurredmany clinical trials worldwide. Early clinical experience hasnot met the great expectations raised, but many lessons are beinglearned in terms of biological activity and cases of clinical responsein advanced cases are routinely reported. However, someof the trials that reported the most encouraging clinical responseshave confronted controversy due to scientific misconduct orto accumulation of successful cases in the pilot groups of patientsthat were not so reproducible when more patients were studiedunder the same protocols. The current status of the field could beseen as a half empty or a half full bottle. In either case, improvementsare needed from the lab bench to increase therapeuticpotency, even at the risk of side effects

Carcinoembryonic antigen as a target to induce anti-tumor immune responses.

Identification of relevant targets for cancer therapy is a major goal in cancer research. In this field, the identification of tumor antigens has opened the possibility of inducing specific anti-tumor immune responses. Among these antigens, carcinoembryonic antigen (CEA) is especially relevant because CEA is expressed in a wide variety of adenocarcinomas such as colon, rectum, pancreas, gastric, breast, etc. The present review focuses on different strategies to induce anti-CEA immune responses. In a first group of strategies, the antigen is administered using viral and bacterial vectors expressing CEA, dendritic cells loaded with CEA protein, or dendritic cells transfected with DNA or RNA expressing CEA. A second group of strategies is based on immunizations with antigenic peptide determinants from CEA, rather than with immunogens containing the whole protein. This has been possible due to the identification of different peptide determinants from CEA, which when presented by MHC class I molecules, are recognized by T cytotoxic lymphocytes. More recently, due to the importance of CD4(+) T cells in the induction of immune responses, T helper peptides presented by MHC class II molecules have also been identified. To overcome the poor immunogenicity of CEA-derived peptide determinants, a common feature of self-antigens, their sequence has been modified to improve binding to MHC molecules or recognition by T cell receptors. Finally, in order to enhance immunization efficacy, some of these strategies have combined the administration of immunogens and cytokines or co-stimulatory molecules. Some of the immunization protocols developed are being tested in clinical trials with promising results. Thus, CEA may prove to be a valuable target antigen for the therapy of a high number of malignancies.

Characterization of an immunologically conserved epitope from hepatitis C virus E2 glycoprotein recognized by HLA-A2 restricted cytotoxic T lymphocytes.

BACKGROUND/AIMS: Identification of epitopes recognized by cytotoxic T lymphocytes (CTL) in hepatitis C virus (HCV) proteins is of importance because they can be used for vaccination, treatment of infection or monitoring of immune responses. Our purpose was to characterize new CTL epitopes in HCV structural proteins. METHODS: Peptides were synthesized and tested in HLA-A2 binding assays. Binder peptides were used to stimulate peripheral blood mononuclear cells from HCV+ patients and controls, and activity measured in chromium release and ELISPOT assays. RESULTS: Twenty binder peptides were found, and stimulation of HCV+ patient cells with nine peptides showing high binding ability led to the growth of CD8+ CTL recognizing peptide E2(614-622) in association with HLA-A2. Peptide E2(614-622) was recognized by 30% of HLA-A2+ patients with chronic HCV infection, but no responses were observed in control groups. Five peptides derived from region E2(614-622) from 26 different viral isolates bound to HLA-A2 molecules, and all of them but one, containing Phe at position 622, were recognized by E2(614-622) specific CTL. CONCLUSIONS: These results show that peptide E2(614-622) belongs to a highly conserved region of HCV E2, and might be a good candidate to induce anti-HCV CTL responses in HLA-A2+ subjects.

Respuesta inmunitaria en la infección por el virus de la hepatitis C / Immune response in hepatitis C virus infection

La infección por el virus de la hepatitis C (VHC) se caracteriza por la alta tasa de cronificación viral. Aunque los tratamientos antivirales son eficaces en algunos pacientes, todavía queda un porcentaje alto de ellos que permanece crónicamente infectado. El estudio de los mecanismos del sistema inmunitario involucrados en la eliminación viral es importante tanto para el desarrollo de vacunas como para la comprensión de los fenómenos inmunopatológicos asociados a la infección. Aunque todos los pacientes con infección crónica desarrollan anticuerpos f rente a las proteínas virales, el alto grado de mutación de las regiones reconocidas por anticuerpos neutralizantes hace que la respuesta humoral no sea eficaz. Por otro lado, la eliminación de la infección por VHC tras una hepatitis aguda o tras el tratamiento con IFN- , se asocia con una potente respuesta de los linfocitos T CD4 y CD8, junto con un perfil de citocinas Th1. Sin embargo, la infección crónica viene acompañada con bajas respuestas inmunitarias c e l u l a res, así como un perfil de citocinas de tipo Th2.Además de su alta tasa de mutación, el VHC ha desarrollado mecanismos de interacción con componentes celulare s que desempeñan el normal funcionamiento del sistema inmunitario, permitiendo así la evasión de la respuesta y la cronificación viral. Las futuras vacunas, así como los tratamientos frente al VHC, habrán de tener en cuenta estos factores para conseguir una eliminación eficaz de la infección (AU)

Specific and general HLA-DR binding motifs: comparison of algorithms.

Using panels of peptides well characterized for their ability to bind to HLA DR1, DRB1*1101, or DRB1*0401 molecules, algorithms were deduced to predict binding to these molecules. These algorithms consist of blocks of 8 amino acids containing an amino acid anchor (Tyr, Phe, Trp, Leu, Ile, or Val) at position i and different amino acid combinations at positions i+2 to i+7 depending on the class II molecule. The sensitivity (% of correctly predicted binder peptides) and specificity (% of correctly predicted non-binder peptides) of these algorithms, were tested against different independent panels of peptides and compared to other algorithms reported in the literature. Similarly, using a panel of 232 peptides able to bind to one or more HLA molecules as well as 43 non-binder peptides, we deduced a general motif for the prediction of binding to HLA-DR molecules. The sensitivity and specificity of this general motif was dependent on the threshold score used for the predictions. For a score of 0.1, the sensitivity and specificity were 84.7% and 69.8%, respectively. This motif was validated against several panels of binder and non-binder peptides reported in the literature, as well as against 35, 15-mer peptides from hepatitis C virus core protein, that were synthesized and tested in a binding assay against a panel of 19 HLA-DR molecules. The sensitivities and specificities against these panels of peptides were similar to those attained against the panels used to deduce the algorithm. These results show that comparison of binder and non-binder peptides, as well as correcting for the relative abundance of amino acids in proteins, is a useful approach to deduce performing algorithms to predict binding to HLA molecules.

Decreased excretion of nitrate and nitrite in essential hypertensives with renal vasoconstriction.

Most hypertensive patients exhibit increased renal vascular resistance (RVR). This study was designed to investigate whether there exists any relationship between RVR and the production of nitric oxide (NO) in patients with essential hypertension. The study was performed in 49 non-treated patients with mild-to-moderate essential hypertension, and 20 age- and sex-matched normotensive subjects on a controlled sodium diet. Renal hemodynamics was measured in terms of the clearance of para-aminohippuric acid and inulin. Urinary excretion of nitrate and nitrite (NO3- plus NO2-) was determined as an index of NO production. As compared with normotensives, hypertensive patients exhibited higher (P < 0.001) RVR and lower (P < 0.05) urinary excretion of NO3- plus NO2-. With the 100% confidence (upper) limit of the normotensive population as a cut-off point, a subgroup of 30 hypertensives had an abnormally high RVR. The excretion of NO3- plus NO2- was lower (P < 0.005) in hypertensives with high RVR than in normotensives and the remaining hypertensives. No differences were found in the urinary excretion of NO3- plus NO2- between normotensives and hypertensives with normal RVR. Statistically significant associations were seen between diastolic blood pressure and RVR (r = 0.341, P < 0.05) and urinary excretion of NO3- plus NO2- (r = -0.387, P < 0.01) in all hypertensives. These results indicate that there is a subgroup (61%) of hypertensive patients with diminished urine levels of NO3- plus NO2- in which RVR is abnormally increased. Thus, it is suggested that in essential hypertension a diminished renal ability to produce NO by the endothelium may be involved in exaggerated renal vasoconstriction.

Vasoconstriction of the afferent arteriole and defective renal synthesis of nitric oxide in essential hypertension.

This study was designed to investigate whether some relation exists between afferent arteriolar resistance (AAR) and the renal production of nitric oxide (NO) and prostacyclin (PGI2) in 21 patients with untreated essential hypertension and 20 normotensive controls. All subjects were studied in conditions of an unlimited Na+ diet both basally and after a four-hour amino acid infusion. AAR was calculated using Gomez's equations. Renal production of NO and PGI2 were assessed by radioimmunoassay of the urinary excretion of cGMP and 6-keto-PGF1 alpha, respectively. Baseline AAR was higher (P < 0.01) in hypertensives than in normotensives. The baseline urinary excretion of 6-keto-PGF1 alpha and cGMP were similar in the two groups of subjects. AAR diminished (P < 0.005) in normotensives and remained unchanged in hypertensives after amino acid infusion. Urinary excretion of 6-keto-PGF1 alpha was increased similarly in the two groups of subjects after infusion. Urinary excretion of cGMP remained unchanged in normotensives and decreased by 31% in hypertensives after infusion. These findings suggest that afferent vasoconstriction present in hypertensive patients is unresponsive to the vasodilatory manoeuvre of amino acid infusion. This lack of response may be due to a defective renal synthesis of NO in these patients.

Elevated levels of parathyroid hormone in essential hypertensive patients with increased erythrocyte potassium efflux.

Previous observations suggest that Ca(2+)-dependent K+ efflux is increased in erythrocytes from spontaneously hypertensive rats. On the other hand, it has been reported that hyperparathyroidism induces an increase in Ca(2+)-dependent K+ efflux of human erythrocytes. To investigate whether Ca(2+)-dependent K+ efflux is altered in essential hypertension quinine-sensitive K+ efflux was measured in erythrocytes from 20 normotensive controls and 30 nontreated essential hypertensives. The quinine-sensitive K+ efflux was similar for hypertensive patients (593 +/- 20 mmol/L cells/h) as compared with normotensive controls (532 +/- 34 mmol/L cells/h). Ten hypertensives exhibited values of quinine-sensitive K+ efflux above an upper normal limit of 650 mmol/L cells/h. As compared with controls those patients presented elevated plasma levels of parathyroid hormone (P less than .05). In addition, a positive correlation was found between parathyroid hormone and quinine-sensitive K+ efflux in the above ten hypertensives (R = 0.85, P less than .001). These results suggest that an excess of parathyroid hormone may be involved in the increase of Ca(2+)-dependent K+ efflux present in some essential hypertensive patients.

Glomerular nephropathy associated with chronic Q fever.

Of three patients with Coxiella burnetii endocarditis, two developed focal segmental proliferative glomerulonephritis (GN), and the third developed diffuse intracapillary proliferative glomerulonephritis. In one case, a good therapeutic response was followed by partial remission of the renal alterations, but 10 months later there were clinical and histological signs of active glomerular nephropathy, suggesting that the antigenic stimulus persisted. In another case, poor evolution of the infection was accompanied by clinically and histologically aggressive glomerular nephropathy, and advanced renal failure. The third patient, who had diffuse proliferative glomerulonephritis, underwent renal biopsy earlier than the other two cases, and the behavior of the nephropathy has not been aggressive to date. Immunohistopathologic study revealed a diffuse granular deposit of IgM and C3 in all three cases; the first two also presented a discrete linear IgG deposit in the capillary loops. Attempts to identify C burnetii antigen at the glomerular level by immunohistologic techniques failed in two patients. The literature on the association of chronic Q fever with glomerulonephritis is briefly reviewed.

Mycobacterium chelonei peritonitis due to hematogenous dissemination in a continuous ambulatory peritoneal dialysis patient.

Renal failure patients have been found to have a special susceptibility to Mycobacterium infections. In patients undergoing peritoneal dialysis, Mycobacterium chelonei peritonitis, due to penetration through the peritoneal catheter lumen, has been described. In our report, we described a case of disseminated M chelonei infection that began in a Thomas hemodialysis prosthesis and finally resulted in peritonitis of hematogenous origin. The diagnostic and therapeutic peculiarities are discussed.