Dialysate-side urea kinetics. Neural network predicts dialysis dose during dialysis

Determination of the adequacy of dialysis is a routine but crucial procedure in patient evaluation. The total dialysis dose, expressed as Kt/V, has been widely recognised to be a major determinant of morbidity and mortality in haemodialysed patients. Many different factors influence the correct determination of Kt/V, such as urea sequestration in different body compartments, access and cardiopulmonary recirculation. These factors are responsible for urea rebound after the end of the haemodialysis session, causing poor Kt/V estimation. There are many techniques that try to overcome this problem. Some of them use analysis of blood-side urea samples, and in recent years, on-line urea monitors have become available to calculate haemodialysis dose from dialysate-side urea kinetics. All these methods require waiting until the end of the session to calculate the Kt/V dose. In this work, a neural network (NN) method is presented for early prediction of the Kt/V dose. Two different portions of the dialysate urea concentration-time profile (provided by an on-line urea minitor) were analysed: the entire curve A and the first half B, using an NN to predict the Kt/V and compare this with that provided by the monitor. The NN was able to predict Kt/V is the middle of the 4h session (B data) without a significant increase in the percentage error (B data: 6.69%±2.46%; A data: 5.58%±8.77%, mean±SD) compared with the monitor Kt/V.     

Impaired Recovery of CD4+ Cell Counts Following Highly Active Antiretroviral Therapy in Drug-Naïve Patients Coinfected with Human Immunodeficiency Virus and Hepatitis C Virus

Coinfection with the human immunodeficiency virus (HIV) and the hepatitis C virus (HCV) is highly prevalent in southern Europe. However, there are few and contradictory data about the effect of HCV carriage on the response to highly active antiretroviral therapy (HAART). In this study, the recovery of CD4+ T cells following HAART among antiretroviral-naïve patients seropositive for HIV with and without HCV coinfection was investigated. Two hundred one HIV-infected patients without previous exposure to antiretroviral drugs were included in the study. HCV coinfection was detected in 123 (61%) patients. The time to recover 200 CD4+ cells/µl was longer in the HCV-positive group (P<0.001). In a Cox model, HCV infection and lack of persistent HIV viremia (defined as <200 copies/ml) were associated with the time to recover 200 CD4+ cells/µl. The mean increase in CD4+ cell counts was lower in the HCV-positive group during the first year of therapy. HIV/HCV-coinfected patients naïve for antiretroviral therapy show a delayed recovery of CD4+ cell counts after starting HAART.     

Pinealectomy increases ouabain high-affinity binding sites and dissociation constant in rat cerebral cortex.

The effect of the pineal gland on the ouabain high-affinity binding sites (Kd = 3.1 +/- 0.4 nM, Bmax = 246.4 +/- 18.4 fmol/mg protein) in rat cerebral cortex was studied. Pinealectomy increased Bmax (940.7 +/- 42.8 fmol/mg protein) and Kd (7.6 +/- 1.5 nM) while melatonin injection (100 micrograms/kg b.wt.) counteracted these effects, restoring kinetic parameters (Kd = 1.9 +/- 0.05 nM; Bmax = 262.2 +/- 29.6 fmol/mg prot) to control values. Melatonin activity on ouabain binding in vitro did not depend upon a direct effect on the binding sites themselves. However, in competition experiments, melatonin increased binding affinity of ouabain as shown by the decreased IC50 values.     

Currant allergy and the Rosaceae-grass pollen allergy syndrome: a case report.

BACKGROUND: Despite the increasing use of currants in culinary recipes, currant allergy has rarely been reported. OBJECTIVES: To study a case of currant allergy and to explore cross-reactivity between grass pollen and Rosaceae family fruit allergens. METHODS: Skin prick tests to pollen and skin prick-to-prick tests with currants and peach were performed. Specific IgE levels were determined using the CAP method. We prepared a protein extract of 0.1 mg/mL in phosphate-buffered saline using red currant in the presence of protease inhibitors. Immunoblot inhibition studies were performed to explore cross-reactivity between grass pollen and currant allergens. RESULTS: Skin prick test results were positive to Dactylis, arizonic, and olive pollens. Results of skin prick-to-prick tests with fresh red and black currants were negative and positive, respectively, to peach. The specific IgE level was 5.7 KU/L to red currant and 2.92 KU/L to peach (CAP). Western blot analysis with red currant extract revealed specific IgE protein bands of 37 and 26 kDa. Preincubation of sera with extracts from red currant and peach inhibited both IgE bands, and preincubation with Dactylis pollen inhibited the 37-kDa band only. CONCLUSIONS: We report a case of allergy to grass pollen with an oral allergy syndrome involving several fruits from 2 different families of the Rosidae subclass confirmed by in vitro tests. Inhibition studies demonstrated cross-reactivity between different fruits (currant and raspberry) from the Rosidae subclass and were incomplete with grass pollen allergens.     

Chemokine receptors that mediate B cell homing to secondary lymphoid tissues are highly expressed in B cell chronic lymphocytic leukemia and non-Hodgkin lymphomas with widespread nodular dissemination

B cell neoplasms present heterogeneous patterns of lymphoid organ involvement, which may be a result of the differential expression of chemokine receptors. We found that chemokine receptor (CCR)7, CXC chemokine receptor (CXCR)4, or CXCR5, the main chemokine receptors that mediate B cell entry into secondary lymphoid tissues and their homing to T cell and B cell zones therein, were highly expressed in B malignancies with widespread involvement of lymph nodes. Conversely, those pathologies with little or no nodular dissemination showed no expression to very low levels of CCR7 and CXCR5 and low to moderate levels of CXCR4. These findings provide evidence for the role of CCR7, CXCR4, and CXCR5 in determining the pattern of lymphoid organ involvement of B tumors. Functional studies were performed on B malignancies expressing different levels of CCR7, CXCR5, and CXCR4. Multiple myeloma (MM) cells did not express CCR7 nor CXCR5 and did not migrate in response to their ligands; a moderate expression of CXCR4 on MM cells was accompanied by a migratory response to its ligand, CXCL12. By contrast, cells from B cell chronic lymphocytic leukemia (B-CLL) expressed the highest levels of these chemokine receptors and efficiently migrated in response to all ligands of CCR7, CXCR4, and CXCR5. In addition, the migration index of B-CLL cells in response to both of the CCR7 ligands correlated with the presence of clinical lymphadenopathy, thus indicating that the high expression of functional chemokine receptors justifies the widespread character of B-CLL, representing a clinical target for the control of tumor cell dissemination.     

Effects of air pollution on cup a 3 allergen in Cupressus arizonica pollen grains.

BACKGROUND: Cupressaceae is a family of plants resistant to airborne contamination, and its pollen is the main cause of winter allergic respiratory diseases, especially in North America, Japan, and Mediterranean countries. Recently, a major allergen from Cupressus arizonica pollen grains, Cup a 3, was cloned and expressed. OBJECTIVE: To study the effects of air pollution on the expression of Cup a 3, a thaumatinlike protein, in C. arizonica pollen grains using a combination of transmission electron microscopy and immunocytochemical techniques. METHODS: Observations were made in mature and hydrated C. arizonica pollen grains from various regions in Spain with different degrees of air pollution. Specimens were fixed using freezing protocols, and ultrathin sections were incubated with anti-rCup a 3 rabbit polyclonal antibodies. RESULTS: Labeling of Cup a 3 was detected in mature and hydrated C. arizonica pollen grains. It was more intense in pollen from polluted air regions, and abundant gold particles were observed as they were released through the pollen grain walls. Furthermore, gold particles remained abundant in the pollen cytoplasm. The labeling was noticeably lower in pollen grains from unpolluted air regions. CONCLUSIONS: Cup a 3 is present in the cytoplasm and walls of cypress pollen grains during the air dispersion and hydration stages. The abundance of Cup a 3 in pollen grains under polluted air conditions indicates that these cypresses intensify their activity as a defense from environmental pollution, thus strengthening their allergenicity.     

Prevalence of obesity and hyperinsulinemia: its association with serum lipid and lipoprotein concentrations in healthy individuals from Maracaibo,Venezuela

The aim of this study was to analyse the prevalence of obesity and hyperinsulinemia and their association with lipid profile alterations on apparently healthy individuals from Maracaibo, Venezuela. We evaluated 306 men and 41 women, ages ranging from 33 to 65 years. All subjects underwent cardiovascular evaluation and laboratory examination after 10-12 h fasting, for glycaemia, total cholesterol, TG, VLDL-C, LDL-C and HDL-C as well as insulin. Seventy-four percent of men and 56.1% of women showed obesity (BMI > 25 Kg/m2). Men showed high concentrations of TG (48.3%), total cholesterol (40.2%), VLDL-C (48.3%) and LDL-C (33.9%) and low HDL-C levels (48%). The most frequent alteration on the lipid profile in women was high total cholesterol (46%) and LDL-C (51.2%). Men had significantly higher insulin concentrations than women (p < 0.005). After they were classified as obese or non obese, the obese subjects (men and women) showed higher prevalence of lipid profile alterations and insulin concentrations than non obese. The insulin concentration in obese men correlated with BMI, TG, VLDL-C and HDL and, in women with BMI, TG and VLDL-C. In conclusion, a high percentage of men and women in this study showed obesity and this obesity, specially in men, was strongly associated with lipid profile alterations and high insulin concentrations both well known cardiovascular risk factors.     

Patterns of reactivity to lipid transfer proteins of plant foods and Artemisia pollen: an in vivo study

BACKGROUND: Lipid transfer proteins (LTPs) are major allergens of Rosaceae fruits in the Mediterranean area. IgE-cross-reactivity has been demonstrated in vitro among LTPs from peach, apple, chestnut and Artemisia pollen. The aim of this study was to evaluate the reactivity to LTPs from peach, apple, chestnut and Artemisia pollen by means of skin prick tests (SPTs). METHODS: Forty-seven patients allergic to peach (peach group), 20 patients sensitized to Artemisia pollen with no food allergies (Artemisia group), and 12 control subjects were skin tested with fresh peach, as well as with whole extracts and purified LTPs of peach, apple, chestnut and Artemisia pollen. RESULTS: The rates of positive SPTs for peach, apple, chestnut and Artemisia LTPs were, respectively, 91, 77, 23, and 36% in the peach group, and 30, 5, 15 and 40% in the Artemisia group. No response was observed in the control subjects. SPTs with peach LTP strongly correlated with SPTs conducted with fresh peach. In the peach group, the most frequent pattern of reactivity to LTPs was the combination peach-apple (45%), followed by peach-apple-Artemisia-chestnut (21%). Significant correlations were found between peach and apple LTPs, and between Artemisia and chestnut LTPs. Positive SPTs to chestnut LTP were only observed in patients with positive SPTs to Artemisia LTP. All the patients with positive case histories to chestnut reacted to chestnut LTP. CONCLUSIONS: LTPs are plant panallergens with different patterns of cross-reactivity. They are major allergens of Rosaceae fruits and seem to be involved in allergic reactions to unrelated foodstuffs such as chestnut, probably through sensitization to the cross-reactive Artemisia LTP. Rosaceae LTPs could be useful tools for in vivo diagnosis of Rosaceae fruit allergy.     

Eye movements and vestibular-nerve responses produced in the squirrel monkey by rotations about an earth-horizontal axis

Summary The eye movements produced by constant-speed rotations about an earth-horizontal axis (EHA) are similar in the alert squirrel monkey to those observed in other species. During EHA rotations, there are persistent eye movements, including a nonreversing nystagmus at lower rotation speeds and either a direction-reversing nystagmus or sinusoidal eye movements at higher rotation speeds. Horizontal eye movements are produced by barbecuespit (yaw) rotations, vertical eye movements by head-over-heels (pitch) rotations. The responses can be viewed as composed of a bias component, reflected in the nonreversing nature of the nystagmus, and a cyclic component, reflected in the periodic modulation of slow-phase eye velocity as head position varies. Vestibular-nerve recordings in the barbiturate-anesthetized monkey indicate that neither semicircular-canal nor otolith afferents give rise to a directionally specific dc signal which can account for the bias component. Apparently the appropriate dc signal has to be constructed centrally from a sinusoidal or ac peripheral input. The otolith organs are a likely source of this peripheral input, although contributions from the semicircular canals and from somatosensory receptors must also be considered. Our results suggest that the directional information required to distinguish rotation direction, rather than being contained in the discharge of individual otolith afferents, is encoded across a population of afferents. Possible sources of such information are the phase differences in the sinusoidal responses of otolith afferents differing in their functional polarization vectors.Supported by Grants NS 01330 from the National Institutes of Health and NGR-14-001-225 from the National Aeronautics and Space Administration