Fatores prognósticos em pacientes graves com meningite bacteriana adquirida na comunidade e lesão renal aguda / Prognostic factors among critically ill patients with community-acquired acute bacterial meningitis and acute kidney injury

RESUMO Objetivo: Investigar os fatores prognósticos em pacientes graves com meningite bacteriana adquirida na comunidade e lesão renal aguda. Métodos: Estudo retrospectivo com inclusão de pacientes em um hospital terciário dedicado a doenças infecciosas localizado em Fortaleza (CE), com diagnóstico de meningite bacteriana adquirida na comunidade complicada por lesão renal aguda. Investigaram-se os fatores associados a óbito, ventilação mecânica e uso de vasopressores. Resultados: Incluíram-se 41 pacientes, com média de idade de 41,6 ± 15,5 anos, 56% dos quais do sexo masculino. O tempo médio entre a admissão à unidade de terapia intensiva e o diagnóstico de lesão renal aguda foi de 5,8 ± 10,6 dias. A mortalidade global foi de 53,7%. Segundo os critérios KDIGO, 10 pacientes foram classificados como estágio 1 (24,4%), 18 como estágio 2 (43,9%) e 13 como estágio 3 (31,7%). A classificação em estágio KDIGO 3 aumentou de forma significante a mortalidade (OR = 6,67; IC95% = 1,23 - 36,23; p = 0,028). A presença de trombocitopenia não se associou com aumento da mortalidade, porém foi um fator de risco para a ocorrência da classificação KDIGO 3 (OR = 5,67; IC95% = 1,25 - 25,61; p = 0,024) e para necessidade de utilizar ventilação mecânica (OR = 6,25; IC95% = 1,33 - 29,37; p = 0,02). Os pacientes que necessitaram de ventilação mecânica 48 horas após o diagnóstico de lesão renal aguda tiveram níveis mais elevados de ureia (44,6 versus 74mg/dL; p = 0,039) e sódio (138,6 versus 144,1mEq/L; p = 0,036). Conclusão: A mortalidade de pacientes graves com meningite bacteriana adquirida na comunidade e lesão renal aguda é alta. A severidade da lesão renal aguda se associou com mortalidade ainda mais elevada. A presença de trombocitopenia se associou com lesão renal aguda mais grave. Níveis mais elevados de ureia podem prever mais precocemente a ocorrência de lesão renal aguda de maior gravidade.

ABSTRACT Objective: To investigate prognostic factors among critically ill patients with community-acquired bacterial meningitis and acute kidney injury. Methods: A retrospective study including patients admitted to a tertiary infectious disease hospital in Fortaleza, Brazil diagnosed with community-acquired bacterial meningitis complicated with acute kidney injury. Factors associated with death, mechanical ventilation and use of vasopressors were investigated. Results: Forty-one patients were included, with a mean age of 41.6 ± 15.5 years; 56% were males. Mean time between intensive care unit admission and acute kidney injury diagnosis was 5.8 ± 10.6 days. Overall mortality was 53.7%. According to KDIGO criteria, 10 patients were classified as stage 1 (24.4%), 18 as stage 2 (43.9%) and 13 as stage 3 (31.7%). KDIGO 3 significantly increased mortality (OR = 6.67; 95%CI = 1.23 - 36.23; p = 0.028). Thrombocytopenia was not associated with higher mortality, but it was a risk factor for KDIGO 3 (OR = 5.67; 95%CI = 1.25 - 25.61; p = 0.024) and for mechanical ventilation (OR = 6.25; 95%CI = 1.33 - 29.37; p = 0.02). Patients who needed mechanical ventilation by 48 hours from acute kidney injury diagnosis had higher urea (44.6 versus 74mg/dL, p = 0.039) and sodium (138.6 versus 144.1mEq/L; p = 0.036). Conclusion: Mortality among critically ill patients with community-acquired bacterial meningitis and acute kidney injury is high. Acute kidney injury severity was associated with even higher mortality. Thrombocytopenia was associated with severer acute kidney injury. Higher urea was an earlier predictor of severer acute kidney injury than was creatinine.

Encefalopatía hiperamoniémica secundaria a infección urinaria por germen productor de ureasa: Caso clínico pediátrico / Hyperammonemic encephalopathy due to urinary tract infection by urea splitting bacteria: A pediatric case report

El incremento del amonio en sangre, hiperamoniemia, es pasible de provocar compromiso neurológico al atravesar la barrera hematoencefálica. La causa más frecuente y conocida de hiperamoniemia es la alteración en la función hepática. Sin embargo, se deben considerar otras patologías, de menor frecuencia y poco conocidas. La infección del tracto urinario por gérmenes productores de ureasa debe ser contemplada a pesar de ser infrecuente en pediatría. Se reporta el caso de un niño con encefalopatía aguda grave, con niveles elevados de amonio en sangre, en quien, luego de descartar otros diagnósticos diferenciales, se asumió el cuadro como hiperamoniemia secundaria a infección del tracto urinario por Corynebacterium riegelii, un germen productor de ureasa. Se implementaron medidas generales de tratamiento para la encefalopatía hiperamoniémica y tratamiento antibiótico específico, con buena evolución el paciente.

Elevated level of ammonia in the blood, defined as hyperammonemia, is feasible to cause neurological symptoms when crossing the blood-brain barrier. The most frequent and studied cause of hyperammonemia is liver failure. Nevertheless, other less frequent and known etiologies must be considered. Urinary tract infection caused by urea-splitting bacteria, despite being unusual in pediatric patients, must be taken into account. We report a pediatric patient with severe acute encephalopathy and high levels of ammonia in blood. After ruling out other causes of hyperammonemia, it was assumed secondary to urinary tract infection by Corynebacterium riegelii, a ureasplitting bacteria. General treatment for hyperammonemic encephalopathy was established, as well as specific treatment with antibiotics. The patient evolved favorably.

Glicerina associada à ureia na terminação de bovinos: parâmetros ruminais, digestibilidade e massa microbiana / Glycerin associated with urea in finishing cattle: ruminal fermentation, digestibility and microbial mass

O objetivo desta pesquisa foi verificar a combinação de glicerina com ureia, quanto aos parâmetros ruminais, à digestibilidade e à qualidade da massa microbiana. O trabalho foi conduzido na Unidade Animal de Estudos Digestivos e Metabólicos, pertencente à Faculdade de Ciências Agrárias e Veterinárias-FCAV/Unesp, Câmpus de Jaboticabal. Seis animais da raça Nelore providos de cânulas ruminais foram utilizados para verificar os parâmetros pH, nitrogênio amoniacal, a digestibilidade e a massa microbiana, distribuídos em quadrado latino 6x6. Seis dietas com energia metabolizável e proteína bruta semelhantes foram formuladas, utilizando-se a proporção volumoso:concentrado de 30:70. O volumoso utilizado foi silagem de milho. Os concentrados utilizados foram compostos por milho, casca de soja, farelo de girassol, glicerina e ureia. Os tratamentos foram: C = controle; U = 1% de ureia; G10 = 10% de glicerina; GU10 = 1% de ureia e 10% de glicerina, G20 = 20% de glicerina e GU20 = 20% de glicerina e 1% de ureia. Houve influência das dietas no crescimento dos microrganismos ruminais, no pH e no nitrogênio amoniacal. Dietas com 20% de glicerina na matéria seca da dieta diminuem a população de protozoários ruminais. A inclusão de glicerina diminui a digestibilidade de componentes fibrosos da dieta.(AU)

The aim of this research was to investigate the combination of glycerol with urea as the ruminal parameters, digestibility and quality of microbial mass. The work was conducted at the Animal Unit of Digestive and Metabolic Studies belonging to the Faculty of Agricultural Sciences and Veterinárias-FCAV/Unesp campus Jaboticabal. Six animals fitted with rumen cannulas Nellore were used to verify the parameters pH, ammonia nitrogen, digestibility, and microbial mass distributed in a 6x6 Latin square. Six diets with similar metabolizable energy and crude protein were formulated using the forage:concentrate ratio of 30:70. The roughage used was corn silage. The concentrates used were composed of corn, soybean hulls, sunflower meal, glycerin and urea. The treatments were: C = control, U = 1 % urea, G10 = 10 % glycerin, GU10 = 1 % urea and 10 % glycerol, G20 = 20 % glycerin and GU20 = 20 % glycerin and 1 % urea. Diets with glycerin had lower digestibility of NDF and hemicellulose. There was no influence of diets on the growth of rumen microorganisms, pH and ammonia nitrogen. Diets with 20 % glycerin in the diet dry matter decrease the population of rumen protozoa. The addition of glycerol decreases the digestibility of fibrous components of the diet.(AU)

Biomineralization of a calcifying ureolytic bacterium Microbacterium sp. GM-1

Background: Biomineralization is a significant process performed by living organisms in which minerals are produced through the hardening of biological tissues. Herein, we focus on calcium carbonate precipitation, as part of biomineralization, to be used in applications for environmental protection, material technology, and other fields. A strain GM-1, Microbacterium sp. GM-1, isolated from active sludge, was investigated for its ability to produce urease and induce calcium carbonate precipitation in a metabolic process. Results: It was discovered that Microbacterium sp. GM-1 resisted high concentrations of urea up to 60 g/L. In order to optimize the calcification process of Microbacterium sp. GM-1, the concentrations of Ni2+ and urea, pH value, and culture time were analyzed through orthogonal tests. The favored calcite precipitation culture conditions were as follows: the concentration of Ni2+ and urea were 50 µM and 60 g/L, respectively, pH of 10, and culture time of 96 h. Using X-ray diffraction analysis, the calcium carbonate polymorphs produced by Microbacterium sp. GM-1 were proven to be mainly calcite. Conclusions: The results of this research provide evidence that Microbacterium sp. GM-1 can biologically induce calcification and suggest that strain GM-1 may play a potential role in the synthesis of new biominerals and in bioremediation or biorecovery.

Variation of Spirulina maxima biomass production in different depths of urea-used culture medium

Fewer studies have assessed the outdoor cultivation of Spirulina maxima compared with S. platensis, although the protein content of S. maxima is higher than S. platensis. Spirulina growth medium requires an increased amount of NaHCO3, Na2CO3, and NaNO3, which increases the production cost. Therefore, the current study used a low-cost but high-efficiency biomass production medium (Medium M-19) after testing 33 different media. The medium depth of 25 cm (group A) was sub-divided into A1 (50% cover with a black curtain (PolyMax, 12 oz ultra-blackout), A2 (25% cover), and A3 (no cover). Similarly the medium depths of 30 and 35 cm were categorized as groups B (B1, B2, and B3) and C (C1, C2, and C3), respectively, and the effects of depth and surface light availability on growth and biomass production were assessed. The highest biomass production was 2.05 g L-1 in group A2, which was significantly higher (p < 0.05) than that in all other groups and sub-groups. Spirulina maxima died in B1 and C1 on the fifth day of culture. The biochemical composition of the biomass obtained from A2 cultures, including protein, carbohydrate, lipid, moisture, and ash, was 56.59%, 14.42%, 0.94%, 5.03%, and 23.02%, respectively. Therefore, S. maxima could be grown outdoors with the highest efficiency in urea-enriched medium at a 25-cm medium depth with 25% surface cover or uncovered.

Biomineralization processes of calcite induced by bacteria isolated from marine sediments

Biomineralization is a known natural phenomenon associated with a wide range of bacterial species. Bacterial-induced calcium carbonate precipitation by marine isolates was investigated in this study. Three genera of ureolytic bacteria, Sporosarcina sp., Bacillus sp. and Brevundimonas sp. were observed to precipitate calcium carbonate minerals. Of these species, Sporosarcina sp. dominated the cultured isolates. B. lentus CP28 generated higher urease activity and facilitated more efficient precipitation of calcium carbonate at 3.24 ± 0.25 × 10−4 mg/cell. X-ray diffraction indicated that the dominant calcium carbonate phase was calcite. Scanning electron microscopy showed that morphologies of the minerals were dominated by cubic, rhombic and polygonal plate-like crystals. The dynamic process of microbial calcium carbonate precipitation revealed that B. lentus CP28 precipitated calcite crystals through the enzymatic hydrolysis of urea, and that when ammonium ion concentrations reached 746 mM and the pH reached 9.6, that favored calcite precipitation at a higher level of 96 mg/L. The results of this research provide evidence that a variety of marine bacteria can induce calcium carbonate precipitation, and may influence the marine carbonate cycle in natural environments.

Influence of environmental hypertonicity on the induction of ureogenesis and amino acid metabolism in air-breathing walking catfish (Clarias batrachus, Bloch).

Effect of environmental hypertonicity, due to exposure to 300 mM mannitol solution for 7 days, on the induction of ureogenesis and also on amino acid metabolism was studied in the air-breathing walking catfish, C. batrachus, which is already known to have the capacity to face the problem of osmolarity stress in addition to other environmental stresses in its natural habitats. Exposure to hypertonic mannitol solution led to reduction of ammonia excretion rate by about 2-fold with a concomitant increase of urea-N excretion rate by about 2-fold. This was accompanied by significant increase in the levels of both ammonia and urea in different tissues and also in plasma. Further, the environmental hypertonicity also led to significant accumulation of different non-essential free amino acids (FAAs) and to some extent the essential FAAs, thereby causing a total increase of non-essential FAA pool by 2-3-fold and essential FAA pool by 1.5-2.0-fold in most of the tissues studied including the plasma. The activities of three ornithine-urea cycle (OUC) enzymes such as carbamoyl phosphate synthetase, argininosuccinate synthetase and argininosuccinate lyase in liver and kidney tissues, and four key amino acid metabolism-related enzymes such as glutamine synthetase, glutamate dehydrogenase (reductive amination), alanine aminotransaminase and aspartate aminotransaminase were also significantly up-regulated in different tissues of the fish while exposing to hypertonic environment. Thus, more accumulation and excretion of urea-N observed during hypertonic exposure were probably associated with the induction of ureogenesis through the induced OUC, and the increase of amino acid pool was probably mainly associated with the up-regulation of amino acid synthesizing machineries in this catfish in hypertonic environment. These might have helped the walking catfish in defending the osmotic stress and to acclimatize better under hypertonic environment, which is very much uncommon among freshwater teleosts.

Avaliação da associação entre as alterações no metabolismo mineral e o prurido nos pacientes em hemodiálise / Evaluating the association between alterations in mineral metabolism and pruritus in hemodialysis patients

FUNDAMENTOS: prurido é o sintoma mais freqüente nos pacientes nefropatas em hemodiálise. Parâmetros laboratoriais anormais têm sido encontrados, com dados conflitantes. OBJETIVO: relacionar a prevalência de prurido com alterações no metabolismo mineral de pacientes em hemodiálise. MÉTODOS: estudo caso-controle. Avaliados 105 pacientes, sendo os pacientes com prurido os casos, preencheram o questionário do protocolo de pesquisa e a escala análoga visual, os dados laboratoriais foram coletados dos prontuários eletrônicos. RESULTADOS: a média de idade foi de 51,9 anos, 59 por cento dos pacientes eram homens e 43 por cento dos pacientes tinham prurido. Xerodermia ocorreu em 45 por cento dos pacientes. Níveis elevados de Ca foram demonstrados em 55 por cento dos pacientes e 47 por cento tinham prurido. Quanto ao fósforo 60 por cento tinham valores elevados e 43 por cento tinham prurido. A relação Ca/P foi normal em todos. O paratormônio mostrou-se elevado em 95 por cento dos pacientes, todos referindo prurido. CONCLUSÃO: houve associação estatisticamente significativa entre o grupo de pacientes com prurido e xerodermia. Os níveis séricos de Cálcio, Fósforo, relação Ca/P, PTHi e o tamanho do dialisador não apresentaram associação estatisticamente significativa com o prurido. Logo, encontramos relação importante entre xerodermia e prurido, sem relação com os parâmetros laboratoriais avaliados.

BACKGROUND: Uremic pruritus is the most frequent symptom in long-term hemodialysis patients. Abnormal laboratory parameters have been found with conflicting data. OBJECTIVE: To correlate the prevalence of pruritus with alterations in mineral metabolism in hemodialysis patients. METHODS: This was a case-control study. A hundred and five patients on maintenance hemodialysis were evaluated: a group of patients with pruritus and a control group. They answered a research protocol questionnaire; laboratory data were collected from medical records and the patients with pruritus filled out a visual analogue scale (VAS) to measure pruritus level. RESULTS: The mean age was 51.9 years; 59 percent of the patients were men and 43 percent of the patients had pruritus. Xeroderma occurred in 45 percent of the patients. High levels of calcium were demonstrated in 55 percent of the patients and 47 percent had pruritus. 60 percent of the patients had high phosphorus levels and 43 percent had pruritus. The Ca/P ratio was normal for all the patients. Parathyroid hormone was high in 95 percent of the patients, all of them referring pruritus. CONCLUSION: There was a statistically significant association between the group of patients with pruritus and xeroderma. Serum calcium and phosphorus levels, Ca/P ratio, PTHi and size of the dialyzer did not show a statistically significant association with pruritus. Therefore, we found an important relationship between xeroderma and pruritus, with no relation with the assessed laboratory parameters.

tlpA gene expression is required for arginine and bicarbonate chemotaxis in Helicobacter pylori

About half of the human population is infected with Helicobacter pylori, a bacterium causing gastritis, peptic ulcer and progression to gastric cancer. Chemotaxis and flagellar motility are required for colonization and persistence of H. pylori in the gastric mucus layer. It is not completely clear which chemical gradients are used by H. pylori to maintain its position. TlpA, a chemotaxis receptor for arginine/ bicarbonate, has been identified. This study aimed to find out whether tlpA gene expression is required for the chemotactic response to arginine/bicarbonate. Wild-type motile H. pylori ATCC 700392 and H. pylori ATCC 43504, a strain having an interrupted tlpA gene, were used. Also, a tlpA-knockout mutant of H. pylori 700392 (H. pylori 700-tlpA::cat) was produced by homologous recombination. Expression of tlpA was assessed by a Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) assay. Chemotaxis was measured as a Relative Chemotaxis Response (RCR) by a modified capillary assay. H. pylori 700392 presented chemotaxis to arginine and sodium bicarbonate. H. pylori 700-tlpA::cat showed neither tlpA gene expression nor chemotaxis towards arginine and bicarbonate. Besides confirming that TlpA is a chemotactic receptor for arginine/bicarbonate in H. pylori, this study showed that tlpA gene expression is required for arginine/bicarbonate chemotaxis.

Antibody response following Hepatitis B vaccination in peritoneal dialysis patients: does normalized urea clearance matter?

OBJECTIVES: Data on the factors that contribute to the antibody response to hepatitis B virus vaccination in peritoneal dialysis patients are scarce. The current study was conducted on a group of peritoneal dialysis patients to learn how the response to hepatitis B virus vaccination varies according to the patient's clearance of urea normalized to total body water (Kt/V). METHODS: A convenience sample of 33 peritoneal dialysis patients (13 women and 20 men, with a mean age of 49¡12 years) was administered double doses (20 μg IM in each deltoid muscle) of recombinant hepatitis B vaccine at 0, 1, 2, and 6 months. Response to immunization was measured at one to three months after the final dose of vaccine. The subjects were divided into groups according to the level of antibodies to hepatitis B surface antigen (anti-HBs), including non-responders ( < 10 IU/L), weak responders (10-100 IU/L), and good responders ( > 100 IU/L). RESULTS: Among non-responders, weak responders, and good responders, significant differences were found in age (54 ± 12 vs. 56 ± 9 vs. 45¡12 years, respectively; p = 0.049) and recombinant human erythropoietin use (20 vs. 29 vs. 76 percent, respectively; p = 0.016). No significant differences in weekly total Kt/V (p = 0.704), weekly peritoneal Kt/V (p = 0.064) and residual glomerular filtration rate (p = 0.355) were found across the three groups. CONCLUSIONS: Delivered clearance measured by weekly peritoneal Kt/V and total clearance measured by weekly total Kt/V did not predict the response to hepatitis B virus vaccination in patients on peritoneal dialysis.

Estimation of amino acids, urea and uric acid in tasar silkworm, Antheraea mylitta Drury.

The tasar silkworm, Antheraea mylitta Drury, Andhra local ecorace is an exclusive race of Andhra Pradesh. It is on the verge of extinction due to difficulty of acclimatisation at breeding and rearing stages. As an attempt to protect this race, a method of total indoor rearing has been done. In this context, the estimation of free amino acids, excretory products- urea and uric acid were compared during the fourth and fifth instars of tasar silkworm, reared under outdoor and indoor conditions. The study has revealed that amino acids decreased in the fat body in outdoor and indoor reared larvae in contrast to that in the haemolymph where it has gradually increased from first to third crops. This is an important finding as it reveals that indoor worms seem to adopt proteolytic activity in the haemolymph. Secondly, in the fifth instar the excretory products are more compared to fourth instar in the indoor reared worms. During fifth instar, formation of nitrogenous products lessens as silk synthesis enhances. The present study reveals that decrease in uric acid in fifth instar implies increase in growth rate and silk synthesis in both outdoor and indoor worms. The findings of the present investigation is helpful in the conservation and protection of the A. mylitta, Andhra local ecorace.

Mitochondrial citrulline synthesis from ammonia and glutamine in the liver of ureogenic air-breathing catfish, Clarias batrachus (Linnaeus).

The possible synthesis of citrulline, a rate limiting step for urea synthesis via the ornithine-urea cycle (OUC) in teleosts was tested both in the presence of ammonia and glutamine as nitrogen-donating substrates by the isolated liver mitochondria of ureogenic air-breathing walking catfish, C. batrachus. Both ammonia and glutamine could be used as nitrogen-donating substrates for the synthesis of citrulline by the isolated liver mitochondria, since the rate of citrulline synthesis was almost equal in presence of both the substrates. The citrulline synthesis by the isolated liver mitochondria requires succinate at a concentration of 0.1 mM as an energy source, and also requires the involvement of intramitochondrial carbonic anhydrase activity for supplying HCO3 as another substrate for citrulline synthesis. The rate of citrulline synthesis was further stimulated significantly by the isolated liver mitochondria of the fish after pre-exposure to 25 mM NH4Cl for 7 days. Due to possessing this biochemical adaptational strategy leading to the amelioration of ammonia toxicity mainly by channeling ammonia directly and/or via the formation of glutamine to the OUC, this air-breathing catfish could succeed in surviving in high external ammonia, which it faces in its natural habitat in certain seasons of the year.

Clinical and mycological profile of cryptococcosis in a tertiary care hospital.

This study examined the extent of cryptococcosis in clinically diagnosed cases of meningitis in HIV-1 seropositive and apparently immunocompetent patients. One hundred and forty-six samples, obtained from 126 chronic meningitis patients comprised of cerebrospinal fluid (CSF), blood, sputum and urine. The samples were processed by standard microbiological procedures. Cryptococcal isolates were identified by microscopy, cultural characteristics, melanin production on niger seed agar and hydrolysis of urea. The isolates were further speciated on cannavanine glycine bromothymol blue (CGB) media. Cryptococcal antigen detection of CSF samples was performed by latex agglutination test (LAT). Minimum inhibitory concentration (MIC) of amphotericin B for the isolates was also tested. Cryptococcosis was diagnosed in 13 patients (eight HIV-1 seropositive and five apparently immunocompetent). Cryptococcus neoformans var. neoformans was the predominant isolate. Cryptococcal antigen was detected in all, whereas microscopy could detect yeast cells in nine patients. The isolates were sensitive to amphotericin B. CD4 cell counts ranged from 8 to 96/cu mm. The study concludes that all CSF samples with clinical diagnosis of subacute and chronic meningitis should be subjected to tests for detection of Cryptococcus in clinical laboratory irrespective of the immune status.

Associations between Sympathetic Activity, Plasma Concentrations of Renin, Aldosterone, and Parathyroid Hormone, and the Degree of Intractability of Blood Pressure Control in modialysis Patients

This study was designed to examine how such factors as hemodialysis parameters, body mass index, renin and aldosterone concentrations, sympathetic nervous activity, and parathyroid hormone concentrations are associated with the control of hypertension in hemodialysis patients. Hemodialysis patients (n=114) were grouped into four categories. Group 1 had normal BP without antihypertensive medication. Group 2 needed one antihypertensive drug, Group 3 needed combination of two or three categories of antihypertensive drugs without minoxidil. Group 4 needed more than three categories of antihypertensive drugs including minoxidil. Parathyroid hormone, beta2-microglobulin, renin and aldosterone, epinephrine, norepinephrine, and hemodialysis parameters were measured. The fractional clearance of urea as Kt/V urea was significantly lower in Group 3 and Group 4 than in Group 2 (p<0.01). Concentrations of parathyroid hormone were significantly higher in Group 4 than the other groups (p<0.01). Pre-hemodialysis norepinephrine concentrations were significantly higher in Group 4 than the other groups (p<0.05). Traditional factors associated with hypertension did not seem to be relevant to the degree of hypertension in hemodialysis patients in the present study. In conclusion, poor Kt/V urea, elevated parathyroid hormone concentrations, and elevated concentrations of plasma norepinephrine seemed to be the factors that might be associated with control of hypertension in hemodialysis patients.

Análisis de la polaridad estructural y funcional de estructuras tridimensionales (esferoides) de células hepáticas porcinas cultivadas in vitro / Structural and functional polarity of porcine hepatocyte cultured spheroids

Los hepatocitos son células epiteliales polarizadas que, al ser aisladas y cultivadas, pierden la polaridad y las propiedades de célula diferenciada. El cultivo de células hepáticas como esferoides permite obtener estructuras con organización de tipo tisular. En este trabajo se analizó estructural y funcionalmente la polaridad de esferoides porcinos. Para ello, las células hepáticas porcinas fueron aisladas y cultivadas en agitación constante. La actividad metabólica de los esferoides fue probada mediante el metabolismo de diazepam y de amonio, así como con síntesis de albúmina. Sus características estructurales mostraron la polaridad de las células. Fueron observados paquetes de fibras de colágeno distribuidas irregularmente y fibras reticulares en formahomogénea en todo el volumen del esferoide. Se hallaron células Ck19+ formando estructuras tipo ducto biliar, así como también _ y _-cateninas y pan-cadherinas en diferentes zonas, especialmente en las laminas externas, con características de epitelio cuboidal. Por microscopía electrónica de barrido se observaron estructuras muy compactas con superficie lisa, y por microscopía electrónica de transmisión, canalículos biliares con microvellosidades, uniones tight, zonula adherens y desmosomas. Las organelas celulares como mitocondrias, núcleos, nucleolos, peroxisomas, retículo endoplásmico estaban bien conservadas. Una compleja red de canalículos biliares fue observada mediante la incorporación y excreción de un análogo de sal biliar fluorescente. El análisis de los ácidos biliares excretados mostró un patrón normal. La morfología y funcionalidad de los esferoides puede aportar un modelo apropiado para aplicaciones en las que es primordial mantener las funciones específicas del hígado, como un dispositivo de hígado bioartificial.

Hepatocytes are epithelial cells that show a complex polarity in vivo. However, hepatocytes isolated and cultured in vitro normally lose both their differentiated properties and polarity. Culturing hepatocyte spheroids seems to be the accurate approach to maintain tissue level of organization. The structural and functional polaritiesof pig liver spheroids were analyzed in this work. Swine liver cells were isolated and cultured as spheroids. Their metabolic activity was proved through the metabolism of diazepam, ammonium and synthesis of albumin. Several structural features show the presence of polarity in the cells inside the spheroids. Reticular and collagen fibers, as well as Ck19(+) cells forming duct-like structures were found. _eta and _-catenins and pancadherins were positive in different regions of the spheroids, mainly in the outer cell layers, which have cuboidal epithelia features. The scanning electron microscopy showed a tightly compacted architecture, with smooth surface. The transmission electron microscopy analysis showed bile canaliculi with microvilli, tight junctions, zonula adherens and desmosome-like junctions. Wellmaintained cellular organelles, as mitochondria, nucleus,nucleolus, peroxisomes, endoplasmic reticulum, were seen in the spheroids. A complex inner bile canaliculinetwork was shown by using a fluorescent bile acid analogue incorporated and excreted by the spheroids. Furthermore, excretion of a normal pattern of bile acids was demonstrated. The morphology and functionality of the spheroids may provide an appropriate model for applications where the maintenance of liver-specific functions is crucial, as a bioartificial liver device.

Assessment of the different methods to predict equilibrated Kt/V in pediatric hemodialysis.

OBJECTIVES: To determine the degree of urea rebound in children on hemodialysis and compare the different calculation models for Kt/V. MATERIAL AND METHOD: The present study was performed in 50 hemodialysis sessions of 5 pediatric patients, 2 males and 3 females, aged 5-18 years, who had received hemodialysis for 7-48 months. Blood urea samples were obtained at the beginning, 70 minutes intradialysis, the end and every 10 minutes for 1 hour post- dialysis. The compared 6 different models of Kt/V were single pool, Daugirdas, equilibrated, rate equation, Maduell and Smye method. RESULTS: Urea rebound was found to be completed at least 60 minutes post- dialysis and mean percentage value was 30.68 +/- 9.663. Mean value of equilibrated Kt/V was 1.442 +/- 0.259 while that of single-pool Kt/V calculated by InC1/C2 was 1.705 +/- 0.252 leading to overestimation of Kt/V by 0.265 +/- 0.075. Mean value calculated by Daugirdas method was 2.083 +/- 0.336. Mean values obtained by rate equation, Maduell and Smye methods were 1.485 +/- 0.209, 1.442 +/- 0.209 and 1.379 +/- 0.343 which differed from equilibrated Kt/V by 0.086 +/- 0.058 (p = 0.002), 0.069 +/- 0.063 (p = 0.967) and 0.132 +/- 0.132 (p = 0.015), respectively. CONCLUSION: Urea rebound in pediatric patients is completed at least 60 minutes after cessasion of hemodialysis. Kt/V calculated from single-pool is not suitable for children. The Maduell model gives the best correlation to equilibrated Kt/V when compared to rate equation and Smye models.

Urea breath test for Helicobacter pylori detection: present status.

Helicobacter pylori (H. pylori) is the commonest bacterial pathogen found worldwide and more than half the world population aged 40 years and above is colonized with it. The infection rate is >95 % in some African countries. In 1994, the International Agency for Research on cancer classified H. pylori as a class I carcinogen in humans. It causes chronic active gastritis, duodenal and gastric ulcer and gastric malignancy, and is thought to be associated with coronary artery disease, cerebral stroke, vitamin B12 and iron-deficiency anaemia, etc. Therefore, non-invasive test-and-treatment strategies are widely recommended in primary care settings. Conventionally, H. pylori infection can be diagnosed by invasive techniques using an upper gastrointestinal endoscope for obtaining multiple biopsies from different sites of the stomach for RUT, culture, histological examination, polymerase chain reaction (PCR), etc. and by non-invasive tests such as Urea breath test (UBT), stool antigen test and blood serology. At present, 13/14C-UBT is considered the test of choice for confirmation of H. pylori infection. The UBT is based on the principle, that isotopically labelled urea ingested by an H. pylori--infected patient is rapidly hydrolysed by the microbial urease. The released 13/14CO2 is absorbed across the mucous layer to the gastric mucosa and hence, excreted via the systemic circulation in the breath which is collected and measured. The non-hydrolysed urea is excreted completely in the urine within 3-4 days. 13C-UBT being non-radioactive, 13C-UBT can be used in pregnant women and children, and a user's license is not required. There is still no standard protocol accepted and followed internationally for this test. Although the methods are almost similar, various laboratories/clinics use variable tracer doses, test meals, timings and methods for breath collection, and different cut-off values, which make formal validation studies necessary. This review describes the present status of the UBT and its application in the detection of H. pylori infection.

Aspectos clave del ciclo de la úrea con relacion al metabolismo energético y proteico en vacas lactantes / Key aspects of the urea cicle, related to energetic and proteic metabolism in lactating dairy cows

El uso de altas cantidades de fertilizantes nitrogenados en las lecherías especializadas, ha conducido a cambios importantes en las características nutricionales de los forrajes, incrementando el contenido de nitrogeno total (proteina cruda) y su fracción soluble (fracción) a expensas de la proteína verdadera. Este hecho ha generado un aumento exagerado del contenido de nitrogeno fermentable que aparece como amonio el cual no alcanza a ser utilizado por la flora ruminal y pasacon relativa facilidad al torrente circulatorio; posteriormente debe ser transformado en el higado a area y eliminado en la orina o en la leche. Las vacas lactantes utilizan sus reservas proteicas (ademas del propionato ruminal), a favor de la sintesis de glucosa. Los aminoacidos producto del catabolismo proteico, sufren un proceso de transaminación para confluir, la mayoria de ellos, en el glutamato a partir de Á-cetoglutarato como cetoacido receptor. En el interior de la mitocondria, en presencia dela glutamato deshidrogenasa es liberado el amonio y este, en presencia de la carbamoil C fosfato sintetasa, bicarbonato y dos moles de ATP, forma el carbamoil fosfato (CaP), el que más adelante liberarón área. El amonio libre procedente de la absorción ruminal puede formar también Carbamoil Fosfato (CbP), sin embargo, esta reacción tiene baja afinidad a diferencia de la formación del glutamato a partir del mismo amonio y Á- cetoglutarato. La unión del glutamato con otra molécula de amonio produce glutamina la cual es un vehículo muy empleado por el organismo para deshacerse del amonio a nivel renal. La retención del amonio como glutamato constituye un gasto del Á- cetoglutarato, el cual es un importante precursor de la glucosa con lo que la gluconeogenesis a partir de este metabolito se puede ver disminuida. Paralelamente, el aumento en la actividad ureogênica conlleva al incremento en las necesidades de ciertos aminoácidos, como la metionina, para la...

Effect of Aloe vera (L.) Burm. fil. leaf gel and pulp extracts on kidney in type-II diabetic rat models.

Significant degenerative changes were observed in the kidney tissue of untreated neonatal streptozotocin (n0STZ)-induced type-II diabetic rats. These degenerative changes were diminished in the kidney tissue of diabetic animals given glibenclamide and Aloe leaf gel and pulp extracts. Kidney lipid peroxidation levels were increased in diabetic rats compared to healthy rats; these levels were higher in rats treated with glibenclamide than in those which received Aloe extracts. Serum urea and creatinine levels were higher in diabetic rats in comparison to healthy rats. The administration of Aloe gel extract and glibenclamide decreased serum urea and creatinine levels in comparison to diabetic controls. Only A. vera leaf gel extract showed improvement both in histological and biochemical parameters suggesting a protective effect of A. vera on mild damage caused by type-II diabetes on kidney tissue.