Ricardo Mendes Pereira

Cyclohexane oxidation continues to be a challenge

Abstract Many efforts have been made to develop new catalysts to oxidize cyclohexane under mild conditions. Herein, we review the most interesting systems for this process with different oxidants such as hydrogen peroxide, tert -butyl hydroperoxide and molecular oxygen. Using H 2 O 2 , Na-GeX has been shown to be a most stable and active catalyst. Mesoporous TS-1 and Ti-MCM-41 are also stable, but the use of other metals such as Cr, V, Fe and Mo leads to leaching of the metal. Homogeneous systems based on binuclear manganese(IV) complexes have also been shown to be interesting. When t -BuOOH is used, the active systems are those phthalocyanines based on Ru, Co and Cu and polyoxometalates of dinuclear ruthenium and palladium. Microporous metallosilicates containing different transition metals showed leaching of the metal during the reactions. Molecular oxygen can be used directly as an oxidant and decreases the leaching of active species in comparison to hydrogen peroxide and tert -butyl hydroperoxide. Metal aluminophosphates (metal: Mn, Fe, Co, Cu, Cr V) are active and relatively stable under such conditions. Mn-AlPO-36 yields directly adipic acid, but large amounts of carboxylic acids should be avoided, as they cause metal leaching from the catalysts. Rare earth exchanged zeolite Y also shows good selectivity and activity. In the last part of the review, novel alternative strategies for the production of cyclohexanol and cyclohexanone and the direct synthesis of adipic acid are discussed.

Paracoccidioidomycosis in children: clinical presentation, follow-up and outcome

From February, 1981 to May, 2001, 63 children under 15 y old (ages 2 - 15 y, median = 8 y, mean +/- 1 SD = 8 +/- 3 y) presenting 70 episodes of Paracoccidioidomycosis were admitted. The main clinical manifestations and laboratory features observed upon admission were: lymph node enlargement (87.1%), fever (75.7%), weakness (48.6%), pallor (41.4%), hepatomegaly (40%), splenomegaly (35.7%), anemia (90%), hypergammaglobulinemia (88.5%), eosinophilia (75.5%) and hypoalbuminemia (72.5%). Moderate to severe malnutrition was detected in 35.7% of the episodes (Gomezs criterion). Radiographic and technetium studies showed bone lesions in 20 of the episodes, most of them being multiple lytic lesions, involving both long (70%) and plain bones (30%). First line treatment consisted of an association of sulfametoxazole-trimethoprin, which was used, exclusively, in 50 episodes. Follow-up of hemoglobin levels, number of eosinophils in the peripheral blood, albumin and gammaglobulin serum levels revealed significant sequential improvement one and six months after hospital admission, being quite useful to evaluate treatment effectiveness. Six patients died (9.3%) and four developed sequelae (6.3%). In conclusion, the juvenile and disseminated forms can be observed in about 70% of the episodes of PCM occurring in children younger than 15 y old, most of them presenting with a febrile lymphoproliferative syndrome associated to anemia, eosinophilia and hypergammaglobulinemia.

Iron(III) and copper(II) catalysed cyclohexane oxidation by molecular oxygen in the presence of tert-butyl hydroperoxide

Abstract In the presence of cyclohexane soluble iron and copper catalysts, tert -butyl hydroperoxide selectively oxidises cyclohexane to cyclohexanol and cyclohexanone (with cyclohexene for the copper catalysts). Under reflux for 24 h, the conversions are 4 to 5% (turnover numbers of 70 to 90) and the selectivities above 90%. Under 25 bar of oxygen at 70°C for 24 h, conversions with the iron catalysts are 9% (turnover numbers of up to 166) but the selectivities are below 80%, as large amounts of adipic acid are also formed. The copper catalysts are more selective under these conditions. Using Cu(tma) 2 the conversion is 11% (turnover number of 192) and the selectivity is 91%. Reactions in the presence of cyclohexanone show that the iron catalysts deactivate by complexation with the adipic acid formed by its over-oxidation. The copper catalysts rapidly produce cyclohexene at the beginning of the reactions; this is further oxidised to cyclohexen-3-one and cyclohexen-3-ol, thus reducing the catalyst activity for cyclohexane oxidation.

Paradoxical reaction to treatment in 2 patients with severe acute paracoccidioidomycosis: a previously unreported complication and its management with corticosteroids.

Paradoxical reactions have never been described in patients with paracoccidioidomycosis or other deep endemic mycoses out of the context of human immunodeficiency virus infection. We describe 2 patients with an acute form of paracoccidioidomycosis who presented with a worsening of their clinical manifestations while on appropriate antifungal treatment. These manifestations were severe and required adjunct corticosteroid therapy.

Risk factors associated with the acquisition of multiresistant bacteria in a pediatric nursery

OBJECTIVE: To identify the risk factors in patients who had a multiresistant bacteria during their staying in a Pediatric Intensive Care Unit and in a pediatric nursery of a tertiary teaching hospital.METHODS: Chart review of the patients who stayed in the units from January, 1995 to July, 1997 and had a multiresistant microorganism isolated (both infection and colonization). A case-control study was done using McNemar test for group comparison and using stepwise logistic regression to select independent risk factors. The following risk factors were tested: prior hospital staying, underlying disease, intensive care unit admission, surgical procedure, urinary catheter, central venous line, ventilator, prior antibiotic therapy and skin lesion.RESULTS: Among 52 patients, 66 multiresistant bacteria were identified (among them, 33 were gram-negative bacilli and 33 were methicillin-resistant S. aureus). The logistic regression analysis of the case-control study identified 2 risk factors: prior antibiotic therapy and skin lesion. A single risk factor was indicated for patients with gram-negative bacilli. Nevertheless, for patients with methicillin-resistant S. aureus, central venous lines and skin lesion were significant.CONCLUSION: Prior antibiotic therapy and skin lesion were the factors associated with the acquisition of multiresistant bacteria. Besides skin lesion, for oxacilin-resistant S. aureus colonized patients, central venous catheter use was a risk factor. The strategies employed to limit the spread of those bacteria in the hospital should consider these three factors.

Dapsone hypersensitivity syndrome in an adolescent during treatment during of leprosy

A 12 y old girl was admitted 24 days after start a WHO multidrug therapy scheme for multibacillary leprosy (dapsone, clofazimine and rifampicin) with intense jaundice, generalized lymphadenopathy, hepatoesplenomegaly, oral erosions, conjunctivitis, morbiliform rash and edema of face, ankles and hands. The main laboratory data on admission included: hemoglobin, 8.4 g/dL; WBC, 15,710 cells/mm3; platelet count, 100,000 cells/mm3; INR = 1.49; increased serum levels of aspartate and alanine aminotransferases, gamma-glutamyl transpeptidase, alkaline phosphatase, direct and indirect bilirubin. Following, the clinical conditions had deteriorated, developing exfoliative dermatitis, shock, generalized edema, acute renal and hepatic failure, pancytopenia, intestinal bleeding, pneumonia, urinary tract infection and bacteremia, needing adrenergic drugs, replacement of fluids and blood product components, and antibiotics. Ten days after admission she started to improve, and was discharged to home at day 39th, after start new supervised treatment for leprosy with clofazimine and rifampicin, without adverse effects. This presentation fulfils the criteria for the diagnosis of dapsone hypersensitivity syndrome (fever, generalized lymphadenopathy, exfoliative rash, anemia and liver involvement with mixed hepatocellular and cholestatic features). Physicians, mainly in geographical areas with high prevalence rates of leprosy, should be aware to this severe, and probably not so rare, hypersensitivity reaction to dapsone.

Synergistic effect of iron and copper oxides supported on silica in the room temperature oxidation of cyclohexane

Abstract The room temperature oxidation of cyclohexane with oxygen/zinc (Gif IV system), catalysed by iron oxide supported on silica, has been studied. It was found that after calcination the iron catalyst does not leach and is very active for oxidation. Using 4 mmol of iron chloride per 0.1 g of silica, cyclohexanone and cyclohexanol (2:1 ratio) were obtained with a turnover number of 425. Substitution of half of the iron used for impregnation by copper chloride increased the turnover number to 885, without changing the product ratio. As copper chloride alone is not active for this reaction, it exhibits a synergistic effect on the iron(III) heterogenized on the silica.

Neuroparacoccidioidomycosis (NPCM): Magnetic Resonance Imaging (MRI) Findings

ObjectiveTo describe the magnetic resonance imaging (MRI) patterns of the central nervous system (CNS) involvement by neuroparacoccidioidomycosis (NPCM).MethodsBetween January 1999 and March 2011, a review of MRI data analysis from 8 cases of NPCM was performed. The following MRI characteristics were examined by an experienced neuroradiologist: topography of lesions, aspects on T1- and T2-weighted images (WI), contrast enhancement, diffusion and spectroscopy.ResultsAll patients had evidence of paracoccidioidomycosis infection outside the nervous system. Regarding CNS involvement, five patients had only supratentorial lesions; three had infra- and supratentorial ones. Meningeal extension occurred in three patients. The lesions were predominantly hyperintense on T1WI. At T2WI, a hypointense component was present in five cases as well as a perilesional abnormal white matter. A ring-enhancement pattern was seen in five cases. Spectroscopy was performed in three patients and showed an increased lipid peak in all of them. In one case, there was also an increased choline peak.ConclusionNPCM is rare, and MRI may help its differentiation from other inflammatory lesions. However, the presence of active infection outside CNS and some imaging characteristics should point to this diagnosis.

Fatores associados às complicações em crianças pré-escolares com pneumonia adquirida na comunidade

OBJECTIVE: To identify socioeconomic factors and clinical factors associated with the development of complications in preschool children hospitalized with community-acquired pneumonia (CAP). METHODS: This was a prospective longitudinal study involving children (12-59 months of age) diagnosed with CAP and admitted to the pediatric wards of two hospitals in the metropolitan area of Campinas, Brazil. Children with cystic fibrosis, heart disease, pulmonary malformations, neurological disorders, or genetic diseases were excluded. The diagnosis of CAP was based on clinical and radiological findings. Data were collected from the medical records and with a semi-structured questionnaire. The subjects were divided into two groups (complicated and uncomplicated CAP). Socioeconomic and clinical variables were compared, and multivariate logistic regression analysis was performed. RESULTS: Of the 63 children included, 29 and 34, respectively, presented with uncomplicated and complicated CAP. No statistically significant differences were found between the groups regarding age at admission, gestational age, birth weight, gender, or socioeconomic variables. Significant differences were found between the groups regarding history of pneumonia (p = 0.03), previous antibiotic therapy (p = 0.004), time elapsed since the onset of CAP (p = 0.01), duration of fever prior to admission (p < 0.001), duration of antibiotic therapy (p < 0.001), and length of hospital stay (p < 0.001). In the multivariate analysis, only duration of fever prior to admission remained in the model (OR = 1.97; 95% CI: 1.36-2.84; p < 0.001). CONCLUSIONS: Biological variables, especially duration of fever prior to admission, appear to be associated with the development of complications in children with CAP.OBJECTIVE To identify socioeconomic factors and clinical factors associated with the development of complications in preschool children hospitalized with community-acquired pneumonia (CAP). METHODS This was a prospective longitudinal study involving children (12-59 months of age) diagnosed with CAP and admitted to the pediatric wards of two hospitals in the metropolitan area of Campinas, Brazil. Children with cystic fibrosis, heart disease, pulmonary malformations, neurological disorders, or genetic diseases were excluded. The diagnosis of CAP was based on clinical and radiological findings. Data were collected from the medical records and with a semi-structured questionnaire. The subjects were divided into two groups (complicated and uncomplicated CAP). Socioeconomic and clinical variables were compared, and multivariate logistic regression analysis was performed. RESULTS Of the 63 children included, 29 and 34, respectively, presented with uncomplicated and complicated CAP. No statistically significant differences were found between the groups regarding age at admission, gestational age, birth weight, gender, or socioeconomic variables. Significant differences were found between the groups regarding history of pneumonia (p = 0.03), previous antibiotic therapy (p = 0.004), time elapsed since the onset of CAP (p = 0.01), duration of fever prior to admission (p < 0.001), duration of antibiotic therapy (p < 0.001), and length of hospital stay (p < 0.001). In the multivariate analysis, only duration of fever prior to admission remained in the model (OR = 1.97; 95% CI: 1.36-2.84; p < 0.001). CONCLUSIONS Biological variables, especially duration of fever prior to admission, appear to be associated with the development of complications in children with CAP.

Hipercalcemia e lesões osteolíticas múltiplas em criança com paracoccidioidomicose disseminada e tuberculose pulmonar

Abstract Objective: To describe the case of a child with paracoccidioido-mycosis who presented hypercalcemia with multipleosteolytic lesions.Description: A 6-year-old boy was admitted with a one-month history of fever and hepatosplenomegaly. Onadmission, he looked sick, pale, and had disseminated lymphadenopathy and hepatosplenomegaly. The laboratoryfindings included anemia (hemoglobin = 6.8 g/dl), eosinophilia (1,222/mm 3 ), thrombocytopenia (102,000/mm ), andhypoalbuminemia (serum albumin = 2.2 g/dl). Paracoccidioides brasiliensis was identified in bone marrow examination.In the second week after admission, the patient presented joint pain, poor activity and difficulty in walking. He presentedhypercalcemia (maximum value = 14.9 mg%) and reduction in renal function, which lasted for two weeks. On the 42ndday after admission, his chest X-ray showed lytic lesions in clavicle, scapula, ribs, and humerus, with bilateral slippedcapital humeral epiphysis. The patient presented nephrocalcinosis and nephrolithiasis, reduction in creatinine clearanceand evidence of tubular lesions. At the end of the second month after admission, Mycobacterium tuberculosis was isolatedin gastric lavage. The child received treatment for paracoccidioidomycosis and tuberculosis and has not had any sequelaefor 3 years.Comments: The development of symptomatic hypercalcemia leading to renal lesion, associated with multipleosteolytic lesions, had never been described in paracoccidioidomycosis. Although pulmonary tuberculosis was diagnosedand could be related to hypercalcemia, the sudden onset of hypercalcemia and its normalization without specific treatmentfor tuberculosis suggests that bone lysis was the most important factor in the genesis of hypercalcemia.J Pediatr (Rio J). 2005;81(4):349-52: Paracoccidioidomycosis, tuberculosis, hypercalcemia, osteolytic lesions,children.OBJETIVO: Descrever o caso de uma crianca com paracoccidioidomicose, que apresentou hipercalcemia associada a multiplas lesoes osteoliticas. DESCRICAO: Menino de 6 anos, internado com historia de febre e hepatoesplenomegalia ha 1 mes. A internacao, apresentava-se em regular estado geral, descorado, com linfonodomegalia generalizada e hepatoesplenomegalia. Os exames laboratoriais identificaram anemia (hemoglobina = 6,8 g/dl), eosinofilia (1.222/mm3), plaquetopenia (102.000/mm3) e hipoalbuminemia (albumina = 2,2 g/dl). Paracoccidioides brasiliensis foi identificado no mielograma. A partir da segunda semana de internacao, apresentou artralgia, hipoatividade e dificuldade a deambulacao, sendo constatada hipercalcemia (dosagem maxima de 14,9 mg%) e reducao da funcao renal, que duraram pouco mais de 2 semanas. No 42o dia de internacao, foram vistas, na radiografia de torax, multiplas lesoes liticas em claviculas, escapulas, costelas e umeros, com escorregamento epifisario de umero bilateral. Apresentou nefrocalcinose e nefrolitiase, com reducao no clearance de creatinina e evidencias de lesao tubular. No final do segundo mes de internacao, na cultura do lavado gastrico, foi identificado Mycobacterium tuberculosis. Recebeu tratamento para paracoccidioidomicose e tuberculose e esta ha mais de 3 anos em acompanhamento, sem nenhuma sequela. COMENTARIOS: O desenvolvimento da hipercalcemia sintomatica, levando a lesao renal e associada a lesoes osseas multiplas e disseminadas, nunca foi descrito em paracoccidioidomicose. Embora tenha sido diagnosticada tuberculose pulmonar, que pode estar relacionada a hipercalcemia, a forma abrupta como se instalou e como se normalizou sem o tratamento especifico para tuberculose sugere que a lise ossea foi o fator mais importante na genese da hipercalcemia.