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Biomedical subjects

A Mas

Publications and source records attributed to A Mas.

At least 55 records · Page 3Linked to original sources
PubMed2000

Prognostic value of a CCR5 defective allele in pediatric HIV-1 infection.

BACKGROUND: A deletion of 32 base pairs in the CCR5 gene (delta32 CCR5) has been linked to resistance to HIV-1 infection in exposed adults and to the delay of disease progression in infected adults. MATERIALS AND METHODS: To determine the role of delta32 CCR5 in disease progression of HIV-1 infected children born to seropositive mothers, we studied a polymerase chain reaction in 301 HIV-1 infected, 262 HIV-1 exposed-uninfected and 47 HIV-1 unexposed-uninfected children of Spanish and Italian origin. Infected children were further divided into two groups according to their rate of HIV-1 disease progression: rapid progressors who developed severe clinical and/or immunological conditions within the second year of life, and delayed progressors with any other evolution of disease. Among the latter were the long-term, non-progressors (LTNP) who presented with mild or no symptoms of HIV-1 infection above 8 years of age. Viral phenotype was studied for 45 delayed progressors. RESULTS: No correlation was found between delta32 CCR5 and mother-to-child transmission of HIV-1. However, the frequency of the deletion was substantially higher in LTNP, compared with delayed (p = 0.019) and rapid progressors (p = 0.0003). In children carrying the delta32 CCRS mutation, the presence of MT-2 tropic virus isolate was associated with a severe immune suppression (p = 0.028); whereas, the presence of MT-2 negative viruses correlated with LTNP (p = 0.010). CONCLUSIONS: Given the rapidity and simplicity of the assay, the delta32 CCR5 mutation may be a useful predictive marker to identify children with delayed disease progression who, consequently, may not require immediate antiretroviral treatment.

Adolescent↗
PubMed1999

Acute quadriplegic myopathy with myosin-deficient muscle fibres after liver transplantation: defining the clinical picture and delimiting the risk factors.

BACKGROUND: In the last few years, rare cases of acute quadriplegic myopathy (AQM*) with myosin-deficient muscle fibres occurring after solid organ transplantation has been reported. The aim of the present study was to review all cases of AQM with myosin deficient fibres seen at our institution among a large series of patients after orthotopic liver transplants (OLT), with special attention to clinical aspects and associated risk factors. Additionally, an extensive review of all ultrastructurally demonstrated cases of AQM in transplant recipients is also included. PATIENTS AND METHODS: Among patients involved in 281 consecutive liver transplant procedures performed in a 4-year period, 3 men and 1 woman developed an arreflexic, flaccid quadriplegia in the immediate postoperative period of OLT. After ruling out other causes of weakness, a muscle biopsy was performed and a loss of thick (myosin) filaments was confirmed by ultrastructural analysis in all cases. Accurate clinical, epidemiological, and evolutive data were recorded. RESULTS: Corticosteroids had been used at usual dosage given to liver transplant recipients; all four patients had several intra- and postoperative complications leading to receiving significantly higher amounts of hemoderivates, to develop renal failure in all cases, and to require a significantly higher number of reoperations within a few days after transplantation than our contemporaneous global series of liver transplant recipients. AQM patients required a significantly longer intensive care unit and hospital stay. Muscular recovery was the rule, but currently a mild myopathic gait remains in three patients. These and other reported cases of AQM do not histologically and clinically differ from AQM seen in other critically ill patients who have not had transplants. CONCLUSIONS: Patients with a complicated intra- and postoperative course of OLT who develop newly acquired acute muscle weakness should be suspected as having acute AQM with myosin-deficient muscle fibres. In this setting, differential diagnosis with other causes of weakness should be carried out, because the prognosis of this myopathy is good with early muscle rehabilitation therapy.

Acute Disease↗
PubMed1999

Improvement in oxygenation by prone position and nitric oxide in patients with acute respiratory distress syndrome.

OBJECTIVE: Inhaled nitric oxide (NO) and prone position improve arterial oxygenation in patients with the acute respiratory distress syndrome. This study was undertaken to assess the combined effects of NO and prone position in these patients. DESIGN: Prospective clinical study. SETTING: General intensive care service in a community teaching hospital. PATIENTS: 14 mechanically ventilated adult patients with the acute respiratory distress syndrome (mean lung injury score 3.23+/-0.27). MEASUREMENTS AND RESULTS: We measured hemodynamic and oxygenation parameters in the supine position and 2 h later in the prone position, before and during inhalation of 10 ppm NO. A positive response in oxygenation was defined as a > or =20% increment in the arterial oxygen tension/fractional inspired oxygen ratio (PaO2/FIO2). In the prone position PaO2/FIO2 increased significantly (from 110+/-55 to 161+/-89 mm Hg, p<0.01) and venous admixture decreased (from 38+/-12 to 30+/-7%, p<0.01) compared to the supine position. Ten of the 14 patients were responders in the prone position. In the supine position, inhalation of NO improved oxygenation to a lesser extent, increasing PaO2/FIO2 to 134+/-64 mm Hg (p<0.01) and decreasing venous admixture to 35+/-12%, (p<0.01). Five of the 14 patients responded to NO inhalation supine and 8 of 14 responded prone (p = 0.22). The combination of NO therapy and prone positioning was additive in increasing PaO2/FIO2 (197+/-92 mm Hg) and decreasing venous admixture (27+/-8%) (p<0.01). This combination also showed a positive oxygenation response on compared to the supine value without NO in 13 of the 14 patients (93 %). NO-induced changes in PaO2/FIO2 were correlated to changes in pulmonary vascular resistance only in the prone position. CONCLUSIONS: In patients with the acute respiratory distress syndrome, the combination of NO and prone position is a valuable adjunct to mechanical ventilation.

Administration, Inhalation↗
PubMed1999

CCR5 genotype and HIV-1 infection in perinatally-exposed infants.

The CCR5 chemokine receptor is required by non-syncytium HIV-1 strains to infect target cells. A 32 base pair deletion (delta32) in the CCR5 gene causes a structural CCR5 modification that does not permit HIV-1 entry into cells. The rate of the CCR5 delta32 was investigated in 137 children born from HIV-infected mothers. Overall, five (10.6%) of 47 HIV-infected infants showed the defect in heterozygosis vs. eight (8.9%) of 90 uninfected children. No CCR5 delta32 homozygotes were found. Interestingly, among infected children, five (21.7%) of 23 showing a slow disease progression were heterozygous for the CCR5 delta32, meanwhile none of the 24 infants with rapid disease course had the deletion (P = 0.022). In conclusion, the CCR5 delta32 defect does not protect against vertical HIV-1 transmission, but is associated with a delayed disease progression in HIV-infected children.

Female↗
PubMed1999

Helicobacter pylori, hyperammonemia and subclinical portosystemic encephalopathy: effects of eradication.

BACKGROUND/AIMS: An involvement of Helicobacter pylori in the development of hepatic encephalopathy in cirrhotic patients has been proposed, but data confirming such an association are lacking. This prospective study aimed to assess whether ammonia levels and indicators of subclinical portosystemic encephalopathy were influenced by H. pylori status in a series of 62 cirrhotic patients. The effects of H. pylori eradication on such parameters were also investigated. METHODS: Fasting blood ammonia levels, mental state, number connection test, flapping tremor, and EEG tracings were recorded at baseline, and in H. pylori-positive patients (as diagnosed by rapid urease test and 14C-urea breath test) these parameters were reassessed 2 months following eradication therapy. RESULTS: In this series of non-advanced cirrhotic patients, the prevalence of H. pylori infection was 52%. No significant differences were observed between H. pylori+ and H. pylori- cases with respect to fasting venous blood ammonia concentration (47+/-24 vs. 43+/-22 micromol/l) or to the remaining parameters assessing portosystemic encephalopathy. In addition, H. pylori eradication failed to induce any significant variation in either fasting blood ammonia levels (from 45+/-23 to 48+/-26 micromol/l) or neurologic disturbances. CONCLUSION: These results indicate that H. pylori infection is not a major contributing factor to either fasting blood ammonia levels or parameters assessing subclinical portosystemic encephalopathy in patients with non-advanced liver cirrhosis.

Aged↗
PubMed1999

Infection with a novel human DNA virus (TTV) has no pathogenic significance in patients with liver diseases.

BACKGROUND/AIMS: A recently identified DNA virus, termed TT virus (TTV), has been associated with post-transfusional hepatitis, and a high prevalence of TTV infection in patients with acute or chronic liver disease of unknown etiology has been reported from Japan, but few data are available about TTV infection in other countries. METHODS: Using hemi-nested-PCR amplification to detect TTV-DNA sequences in serum, we investigated TTV infection in blood donors and in patients with liver diseases of varied etiology. RESULTS: The prevalence of TTV infection was 13.7% in blood donors (23/168), 18.6% in chronic hepatitis C (19/102), 28.6% in chronic hepatitis B (16/56), 29.9% in hepatocellular carcinoma (20/67), 9.1% in cryptogenic chronic liver disease (2/22) and 39.6% in fulminant hepatitis (19/48). The prevalence of TTV infection in patients with virus-induced or idiopathic fulminant hepatitis was similar. Comparison of TTV-infected and non-infected patients did not reveal significant differences concerning demographic, epidemiological or histopathological features. In patients with hepatitis C, response to interferon therapy was not related to TTV infection. Phylogenetic analysis of TTV isolates showed that at least three different types of TTV are present in Spain. CONCLUSIONS: Our data suggest that TTV infection is frequent among blood donors and patients with acute liver disease. However, pathogenic effects associated with TTV infection were not observed.

Acute Disease↗
PubMed1999

Effects of copper exposure in tissue cultured Vitis vinifera.

The present study determined the effects of copper treatment on some biochemical parameters in a closed system. Sauvignon grapevines were cultured in agar and exposed to copper levels ranging from 0.07 to 10 microg Cu/g medium. Chlorophylls, carotenoids, lipids, sucrose, soluble sugars, starch, cellulose, and minerals in root, leaves, and sap were determined. Copper levels over 5 microg Cu/g inhibit root and plantlet development. Copper-exposed plants have higher levels of chlorophylls and carotenoids as well as total lipids. Soluble sugars decrease without changes in starch or sucrose. Copper concentration increases dramatically in roots and leaves. Iron concentrations are lower in leaves, although they increase in roots, with respect to control plants. Sap flow and translocation of essential elements are reduced. Reduction of K translocation can be related to limited use of water by the plant and, thus, reduction in growth and physiological activity.

Carbohydrates↗
PubMed1999

Persistent hypertransaminasemia as the presenting feature of celiac disease.

Asymptomatic persistent hypertransaminasemia unrelated to hepatitis viral infection is a common cause of referral to the hepatologist. Less frequent liver diseases should then be considered, as well as extrahepatic-origin hypertransaminasemia. Celiac disease, although it has repeatedly been reported as a cause of persistent hypertransaminasemia, is often not included in its differential diagnosis in the absence of the classic malabsorption syndrome. We present the cases of four patients sent to a liver unit for evaluation of persistent hypertransaminasemia in whom celiac disease was finally discovered. Our report highlights the importance of including celiac disease in list of conditions potentially responsible for chronic hypertransaminasemia of unknown cause.

Adult↗
PubMed1998

Tropism, coreceptor use, and phylogenetic analysis of both the V3 loop and the protease gene of three novel HIV-1 group O isolates.

HIV-1 has been subdivided into two groups, M and O, based on phylogenetic analysis. To better understand the pathogenesis of group O viruses, we studied biologic and genetic characteristics of two primary isolates from Spain, ES1158.1 and ES1159.1, and one from the United States, MD.1. After viral isolation, we studied the replication kinetics in peripheral blood mononuclear cells (PBMCs) and macrophages, as well as in different cell lines. All three isolates could replicate in both PBMCs and macrophages. Because no syncytium formation was detected in the MT-2 cell line, viruses were classified as non-syncytium inducing (NSI). All three isolates used the CCR5 coreceptor for entry into the human osteosarcoma (HOS) CD4 cells. Phylogenetic analysis of V3 loop sequences showed that ES1158.1 and ES1159.1 isolates were closely related to the ANT70 strain, whereas MD.1 isolate clustered with the MVP-5180 strain in the same branch. Interestingly, all viruses appeared to be more closely related to the MVP-5180 strain when the protease gene was analyzed, although accessible sequences of this region are very limited.

Amino Acid Sequence↗
PubMed1998

Molecular analysis of yeast population dynamics: effect of sulphur dioxide and inoculum on must fermentation.

The effects of sulphur dioxide and a commercial starter inoculum on yeast population dynamics have been analysed by a molecular approach. Yeast identification from fermenting Carinyena grape musts was performed by RFLP's of mtDNA and rRNA-coding DNA. As expected, the use of a commercial inoculum speeded up the start of fermentation, while SO2 addition limited the development of non-Saccharomyces species. However, this effect was also observed with yeast inoculation. Further analysis of population dynamics could lead to a recommendation for the reduction of the dosage of SO2 by the addition of appropriate inoculum of yeasts in the must. Furthermore, the timing of inoculum addition could be modified to allow a proper contribution of non-Saccharomyces species. Molecular biology analysis of population dynamics could provide a tool to efficiently reduce the dosage of SO2 and adjust the timing of inoculum addition.

DNA, Mitochondrial↗
PubMed1998

[Interrelationship between the duration of HIV infection, viral load and CD4 positive lymphocyte count].

BACKGROUND: The decline in CD4+ lymphocytes occurs at different rates in patients with HIV infection. A longer duration of HIV infection and a higher level of viral replication, represented by the viral load, are associated with a lower CD4+ lymphocyte count. However, the interelationship between these variables is still not well known. PATIENTS AND METHODS: 107 HIV-infected patients for whom the date of infection was known, were included in a transversal study, in which the CD4+ lymphocyte count and the plasma viral load were analysed, the last using an isothermal amplification method (NASBA). Patients were not receiving antiretroviral drugs or suffered intercurrent infections at the time of the study. RESULTS: The mean duration of HIV infection was 8.6 +/- 2.9 years. The mean CD4+ lymphocyte count was 366 +/- 264 x 10(6)/l. The mean plasma viraemia was 4.3 +/- 0.9 logs. In a linear regression model, the CD4+ lymphocyte count was explained in 21.7% of cases by the duration of HIV infection, meanwhile the viral load justified up to 36.2 of CD4+ cell variability. When both parameters were combined, up to 58.4% of CD4+ lymphocyte values were explained. In this model, changes of 1 log in viral load had a 4-fold higher effect on the CD4+ cell count than each year of HIV infection. CONCLUSIONS: The duration of HIV infection and, particularly the viral load strongly influences the current CD4+ lymphocyte count, although other variables should exist (virus with syncytium-inducing phenotype, age of the patient and his immunegenetic repertoire) influencing the different decline seen in CD4+ T-cells.

CD4 Lymphocyte Count↗