Anti-tuberculosis neolignans from Piper regnellii.

The present study determined the anti-Mycobacterium tuberculosis activities of supercritical CO2 extracts, neolignans eupomatenoid-5 (1), conocarpan (4) and eupomatenoid-3 (7) and their derivatives (2, 3, 5, 6, and 8) from Piper regnellii, as well as their cytotoxicities. The supercritical CO2 extract from leaves was purified by chromatographic methods, yielding compounds (1), (4) and (7), which were identified by (1)H NMR and comparison with literature data. Anti-M. tuberculosis activity (H37Rv and clinical isolates) was evaluated using a resazurin microtiter assay plate (REMA) to determine the MIC. The cytotoxicity assay was carried out in macrophages J774G.8 by sulforhodamine B colorimetric assay. The supercritical CO2 extracts from leaves and stems, and compound (4) showed activity against M. tuberculosis (MIC 15.6 µg/ml). Compound (1) showed the best activity (MIC 1.9 µg/ml), with good SI. Compounds (7) and (8) showed low activity against M. tuberculosis H37Rv. The derivative compounds did not show increased anti-M. tuberculosis activity. This is the first report, to our knowledge, to describe neolignans from P. regnellii with activity against M. tuberculosis, and compound (1) is a potential candidate for future antituberculosis drugs.

Effects of (-) mammea A/BB isolated from Calophyllum brasiliense leaves and derivatives on mitochondrial membrane of Leishmania amazonensis.

We have previously demonstrated antileishmanial activity on Leishmania amazonensis of the natural (1-2), synthetic (7) and derivatives of coumarin (-) mammea A/BB (3-6) isolated from the dichloromethane extract of Calophyllum brasiliense leaves. The aim of the present study was to evaluate morphological and ultrastructural alterations in Leishmania amazonensis induced by these compounds. In promastigote forms, all seven compounds produced significant morphological and ultrastructural alterations, as revealed by scanning and transmission electron microscopy. The compound 5,7-dihydroxy-8-(2-methylbutanoyl)-6-(3-methylbutyl)-4-phenyl-chroman-2-one (3), the most active antileishmanial with LD50 of 0.9 µM), induced cell shrinkage and a rounded appearance of the cells. Parasites incubated in the presence of compound (3) showed ultrastructural changes, such as the appearance of mitochondrial swelling with a reduction in the density of the mitochondrial matrix and the presence of vesicles inside the mitochondrion, indicating damage and significant change in this organelle; abnormal chromatin condensation, alterations in the nuclear envelope, intense atypical cytoplasmic vacuolization, and the appearance of autophagic vacuoles were also observed. In addition, the compound (3) may be acting to depolarize the mitochondrial membrane potential of the cells, leading to death of the parasite.

Effect of the synthetic coumarin, ethyl 2-oxo-2H-chromene-3-carboxylate, on activity of Crotalus durissus ruruima sPLA2 as well as on edema and platelet aggregation induced by this factor.

We show that ethyl 2-oxo-2H-chromene-3-carboxylate (EOCC), a synthetic coumarin, irreversibly inhibits phospholipase A(2) (sPLA2) from Crotalus durissus ruruima venom (sPLA2r) with an IC(50) of 3.1 +/- 0.06 nmol. EOCC strongly decreased the V(max) and K(m), and it virtually abolished the enzyme activity of sPLA2r as well as sPLA2s from other sources. The edema induced by sPLA2r + EOCC was less than that induced by sPLA2r treated with p-bromophenacyl bromide, which was more efficient at neutralizing the platelet aggregation activity of native sPLA2r. Native sPLA2r induced platelet aggregation of 91.54 +/- 9.3%, and sPLA2r + EOCC induced a platelet aggregation of 18.56 +/- 6.5%. EOCC treatment also decreased the myotoxic effect of sPLA2r. Mass spectrometry showed that EOCC formed a stable complex with sPLA2r, which increased the mass of native sPLA2r from 14,299.34 Da to 14,736.22 Da. Moreover, the formation of this complex appeared to be involved in the loss of sPLA2r activity. Our results strongly suggest that EOCC can be used as a pharmacological agent against the sPLA2 in Crotalus durissus sp. venom as well as other sPLA2s.

Structure of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase complexed with chalepin, a natural product inhibitor, at 1.95 A resolution.

The structure of the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) from Trypanosoma cruzi complexed with chalepin, a natural product from Pilocarpus spicatus, has been determined by X-ray crystallography to 1.95 A resolution. The structure is in the apo form without cofactors in the subunits of the tetrameric gGAPDH in the asymmetric unit. Unequivocal density corresponding to the inhibitor was clearly identified in one monomer. The final refined model of the complex shows extensive conformational changes when compared with the native structure. The mode of binding of chalepin to gGAPDH and its implications for inhibitor design are discussed.

Toxicity of synthetic piperonyl compounds to leaf-cutting ants and their symbiotic fungus.

The development of Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens was inhibited in vitro by synthetic compounds containing the piperonyl group. In addition, worker ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls. The inhibition of the fungal growth increased with the size of the carbon side chain ranging from C1 through C8 and decreasing thereafter. 1-(3,4-Methylenedioxybenzyloxy)octane (compound 5) was the most active compound and inhibited the fungal development by 80% at a concentration of 15 micrograms ml-1. With worker ants the toxic effects started with compound 5 and increased with the number of carbons in the side chain. Thus, for the same concentration (100 micrograms ml-1) the mortality rates observed after 8 days of diet ingestion were 82%, 66% and 42%, for 1-(3,4-methylenedioxybenzyloxy)decane, 1-(3,4-methylenedioxybenzyloxy)dodecane and compound 5, respectively, whereas with commercial piperonyl butoxide the mortality was 68%. The latter compound, which is known as a synergist insecticide, was as inhibitory to the symbiotic fungus as the synthetic compound 5. The possibility of controlling these insects in the future using compounds that can target simultaneously both organisms is discussed.

Congenital tuberculosis presenting as sepsis syndrome: case report and review of the literature.

We report an infant with congenital tuberculosis who presented with fulminant septic shock, disseminated intravascular coagulation and respiratory failure. Aggressive resuscitation and supportive care and prompt initiation of antituberculosis medications led to resolution of the shock state. We reviewed six other cases with a similar presentation. Congenital tuberculosis should be in the differential of the infant presenting acutely with sepsis syndrome.

Hepatosplenic cat-scratch disease in children: selected clinical features and treatment.

We reviewed 19 cases of hepatosplenic cat-scratch disease at Texas Children's Hospital (Houston). The range of the patients' ages was 2 years 4 months to 11 years 8 months. The chief complaint was fever for all patients. The duration of fever before diagnosis was 7 to 56 days (mean, 22 days). Abdominal pain was present in 13 patients (68%). Thirteen children were treated with rifampin alone, and three received rifampin therapy plus gentamicin or trimethoprim-sulfamethoxazole. Once rifampin therapy was initiated alone or in combination, improvement was noted within 1 to 5 days (mean, 2.6 days) for patients who had had prolonged fever the duration of which before rifampin therapy averaged 3 weeks. The most common dosage and duration for our patients were 20 mg/[kg x d] every 12 hours and 14 days, respectively. Rifampin should be considered in the initial antimicrobial treatment of hepatosplenic cat-scratch disease.

Unique aspects of tuberculosis in the pediatric population.

Therapeutic drug monitoring is a process that allows clinicians to quantitate and control drug therapy. Serum concentration data allow for the explicit determination of pharmacokinetic and pharmacodynamic parameters for individual patients. This information assists the clinician in designing treatment regimens that produce a therapeutic response while minimizing avoidable toxicity. In particular, patients with clinically advanced mycobacterial infections, those with infections caused by strains of M. tuberculosis with acquired drug resistance, or species of nontuberculosis which are inherently drug-resistant, and those with co-morbid conditions such as AIDS may benefit from this process.

Suppurative thrombophlebitis in children: a ten-year experience.

OBJECTIVE: To determine the clinical and diagnostic features, complications, management and prevention of superficial suppurative thrombophlebitis (ST) in children < 18 years of age. STUDY DESIGN: A retrospective review of medical records was performed for patients in two urban hospitals from January 1, 1985, through June 30, 1995, with a discharge diagnosis of phlebitis. RESULTS: We identified 21 patients, including 12 neonates, with ST. The majority had underlying medical conditions or preceding invasive procedures and administration of broad spectrum antibiotics or total parenteral nutrition as possible predisposing factors. More than two-thirds had localizing signs (swelling, erythema, induration or a palpable cord); one-third had purulent drainage from the vein. Septicemia was present in one-third of patients. Fever and tenderness were present in older children. Nearly one-half had involvement of an upper extremity. Cultures of vein (63%), blood (67%) or abscess (86%) grew pathogens in most. Gram-positive organisms were predominant; Staphylococcus aureus was isolated from 44%, Gram-negative enterics from 16.7% and Candida species from another 16.7% of patients. Eleven children had vein excision, whereas 10 had only incision and drainage. Complications, including death in one patient, occurred in 33% but could not be correlated with age or method of surgical intervention. CONCLUSIONS: ST is a rare but serious nosocomial infection in infants and children that results in substantial morbidity. It should be suspected in any hospitalized child who is or was receiving intravenous fluids and who has fever, localizing signs or persistent bacteremia. Prompt vein excision, with adjunctive antimicrobial therapy, is the recommended treatment.

Nontuberculous mycobacterial disease in children.

In most developed countries infections with nontuberculous mycobacteria are causing an increasing proportion of all mycobacterial infections in children. The major clinical syndromes caused by these ubiquitous organisms include pulmonary infections, lymphadenitis, otologic infections, skin and soft tissue infections, indwelling catheter infection, and disseminated infections. Of these, cervical lymphadenitis is the most frequently encountered entity in children, whereas pulmonary infection is rare in this age group. Chronic otorrhea caused by nontuberculous mycobacteria has recently been described. Because many of these infections are similar in presentation to tuberculosis, it is imperative to exclude this diagnosis. The clinical manifestations and management of these infections in children are discussed in this article.

Diagnostic approach to pneumonia in children.

Pneumonia in children may be caused by a variety of agents each requiring a different treatment approach. Lack of a simple and reliable method for establishing an etiologic diagnosis in most cases forces the physician to make therapeutic decisions based on the age of the patient, clinical presentation, radiographic findings, and the knowledge of the likely organisms. When a more specific diagnosis is sought, several noninvasive and invasive techniques are available. Among the first group are sputum examination, cultures of blood, sputum and respiratory tract specimens, rapid antigen detection tests, and serology. Those in the later group, which is usually reserved for critically ill patients or those with underlying immunodeficiency, include pleurocentesis, bronchoalveolar lavage, transbronchial biopsy, and open-lung biopsy. The indications and potential advantages of these tests are discussed in this review.

Immunoglobulin G enhances C3 degradation on coagulase-negative staphylococci.

Antibody and complement are essential to host defense against infection with coagulase-negative staphylococci in the neonate. To evaluate the influence of antibody on C3 deposition, we compared the C3 fragments deposited on coagulase-negative staphylococci after opsonization with normal human serum or with hypogammaglobulinemic serum. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis, the degradation products of C3 were less apparent at 1 and 2 min after opsonization with hypo- and agammaglobulinemic serum than those from normal human serum. This finding suggested that antibody contained in normal human serum contributes to efficient C3 deposition in the early phases of opsonization. There was no clear difference in C3 deposition when slime-producing strains were compared with non-slime-producing strains. The addition of intravenous immunoglobulin to hypogammaglobulinemic serum and serum from premature neonates rendered C3 deposition comparable to that seen with normal human serum. The data from these experiments suggest that the addition of immunoglobulin G may improve host defense against coagulase-negative staphylococci in the hypogammaglobulinemic premature neonate by enhancing C3 deposition, thus promoting opsonophagocytosis of these bacteria.