A solução de sistemas lineares esparsos de alta ordem está inserido em vários ramos da ciência, como por exemplo a engenharia. Por conseguinte, tem havido um grande esforço para resolver ou apresentar soluções aproximadas de tais sistemas de forma eficiente. Neste trabalho combina-se o método da esparsificação recursiva com o algoritmo de Cuthill-McKee para obter uma aproximação esparsa para a inversa de uma classe de matrizes esparsas denominadas matrizes de Hodge.

The solution of sparse linear systems of high order is inserted in various branches of science, such as engineering. Consequently, there has been a great effort to resolve or provide approximate solutions of such systems efficiently. This work combines the method of recursive sparsification with the Cuthill-McKee algorithm for a sparse approximation to the inverse of a class of sparse matrices called Hodge's Matrices.

We present a case of acute hepatitis caused by dengue virus, with a significant increase in aspartate transferase and alanine transferase levels in a chronic hepatitis patient attended at the Cane Sugar Planters Hospital of Campos dos Goytacazes, RJ.

Although adrenocorticotropic hormone is generally considered to play a major role in the regulation of adrenal glucocorticoid secretion, several reports have suggested that other pituitary hormones (e.g., prolactin) also play a significant role in the regulation of adrenal function. The aim of the present study was to measure the adrenocortical cell area and to determine the effects of the transition from the prepubertal to the postpubertal period on the hyperprolactinemic state induced by domperidone (4.0 mg kg-1 day-1, sc). In hyperprolactinemic adult and young rats, the adrenals were heavier, as determined at necropsy, than in the respective controls: adults (30 days: 0.16 ± 0.008 and 0.11 ± 0.007; 46 days: 0.17 ± 0.006 and 0.12 ± 0.008, and 61 days: 0.17 ± 0.008 and 0.10 ± 0.004 mg for treated and control animals, respectively; P < 0.05), and young rats (30 days: 0.19 ± 0.003 and 0.16 ± 0.007, and 60 days: 0.16 ± 0.006 and 0.13 ± 0.009 mg; P < 0.05). We selected randomly a circular area in which we counted the nuclei of adrenocortical cells. The area of zona fasciculata cells was increased in hyperprolactinemic adult and young rats compared to controls: adults: (61 days: 524.90 ± 47.85 and 244.84 ± 9.03 µm² for treated and control animals, respectively; P < 0.05), and young rats: (15 days: 462.30 ± 16.24 and 414.28 ± 18.19; 60 days: 640.51 ± 12.91 and 480.24 ± 22.79 µm²; P < 0.05). Based on these data we conclude that the increase in adrenal weight observed in the hyperprolactinemic animals may be due to prolactin-induced adrenocortical cell hypertrophy.

Múltiplos agentes estão envolvidos na etiopatogenia da diarréia em Aids. O exame de fezes e a colonoscopia são elementos decisivos para o diagnóstico específico. A enterocolite por CMV pode cursar com febre, emagrecimento, diarréia intermitente e hematoquesia. Outros agentes causadores de diarréia podem ter o mesmo espectro de apresentação. OBJETIVO: Definir o perfil clínico da enterocolite por CMV em pacientes com Aids, comparando os parâmetros clínicos, endoscópicos e de tempo de sobrevida entre dois grupos com diarréia crônica, grupo A com CMV e grupo B sem CMV. MÉTODOS: Foram acompanhados 48 pacientes com Aids e diarréia de duração maior que 30 dias, sendo 27 do grupo A e 21 do grupo B. Os parâmetros analisados foram idade, situação de risco, duração da diarréia, hematoquesia, intervalo de tempo entre diagnóstico da infecção por HIV e início de diarréia, achados endoscópicos e sobrevida. Foram realizados exames parasitológicos, culturas e colonoscopia com biópsias. Foi utilizado o teste "t-student" para amostras não pareadas e o teste Qui-Quadrado com correção de Yates para variáveis não paramétricas. Foram construídas curvas de sobrevida pelo método descrito por Kaplan-Meier e aplicado o teste de Mantel - Haenszel. Foi assumido como nível de significância estatística o valor de P menor que 0.05. RESULTADOS: O padrão endoscópico da infecção por CMV correspondeu a ulcerações associadas a hemorragia de submucosa 14 (51.8%) P < 0.01. O tempo de sobrevida do grupo B após o diagnóstico do HIV e após o diagnóstico específico da diarréia foi maior que o do grupo A (0.005 > P > 0.001). Os outros parâmetros estudados não mostraram significância estatística. CONCLUSÕES: A presença de enterocolite por CMV em Aids é marcador de mau prognóstico e menor sobrevida. Existe um padrão endoscópico sugestivo da infecção por CMV.

OBJECTIVE: To determine the clinical profile of CMV colitis in AIDS patients, comparing clinical, endoscopic parameters and survival time between 2 groups of AIDS patients having chronic diarrhea. Group A being CMV colitis and group B without CMV colitis. METHODS: 48 patients with diarrhea that lasted more than 30 days, being 27 in Group A and 21 in Group B, were studied. Age, risk factors, interval time between the diagnosis of HIV infection and the beginning of diarrhea, hematochesia, the endoscopic findings and life table in both groups, were analysed. All of them were diagnosed by stool culture and stools for ovum and parasites, along colonoscopy with biopsies. The unpaired t test was used to assess statistical significance of differences observed in the means of continuous and the chi-square with Yates correction for non-parametric variables. The survival curves were assessed by the Kaplan-Meier and the Mantel-Haenszel's tests. A P value of less than 0,05 was considered to indicate statistical significance. RESULTS: The mucosal lesions associated with the CMV infection are tipically ulcerative on a background of hemorrhagic erythema 14 (51,8%) p < 0,01. The life table analysis disclosed shorter survival time in the CMV colitis group 0,005> P>0,001.The others studied data did not achieve statistical significance. CONCLUSIONS: AIDS patients with CMV colitis have a poorer long-term survival. Among the colonoscopic findings, ulcerations with hemorrhagic background were the most common lesions.

We have demonstrated that acute third ventricle injections of lead acetate (PbAc) exert a powerful antidipsogenic effect and induce a significant increase in renal sodium excretion. In the present study we confirm the antidipsogenic effect of lead and demonstrate that central administration of this metal, in minute amounts, significantly reduces salt intake both during dehydration and after central angiotensinergic stimulation. Adult male Wistar rats had the third ventricle cannulated seven days before the experiments. During this period they had free access to distilled water and hypertonic saline solution (1.5%). After a 24-h period of fluid deprivation, experimental animals received third ventricle injections of PbAc (0.3, N = 8 and 3.0 nmol/rat, N = 14) while controls received sodium acetate (NaAc; 3.0 nmol/rat, N = 10). Rats treated with PbAc at the highest dose showed a significant reduction (P<0.05) both in water and hypertonic saline intake when compared to controls. When the effect of lead administration on angiotensin II-induced water and salt intake was studied, normohydrated animals received third ventricle injections of angiotensin II (9.6 nmol/rat) after pretreatment with 3.0 nmol/rat of PbAc (experimental group, N = 10) or NaAc (controls, N = 8). The group pretreated with PbAc presented a significant reduction (P<0.05) in both water and salt intake compared to controls. Thus, this study confirms the antidipsogenic effect of central lead injections and demonstrates that the presence of lead in the brain exerts a significant inhibition of sodium appetite.